School of Social and Economic Studies

UNIVERSITY OF JUBA

School of Social and Economic Studies

Department of Political Science

SIR 611

Essentials of International Relations

MODULE 13

The International System

Postgraduate Programme in International Relations

Academic Year 2024–2025

Learning Objectives

By the end of this module, students should be able to:

1. Understand the concept of the international system and its significance in the study of international relations.
2. Identify the main characteristics and structures of the international system, including anarchic order, sovereignty, and power distribution.
3. Analyse how the international system shapes and constrains state behaviour across different historical periods.
4. Examine the historical transformations of the international system from ancient times through the Westphalian era to the contemporary post-Cold War order.
5. Evaluate contemporary developments and future trends in the international system, including the rise of emerging powers, globalisation, and new security challenges.

1.0 Introduction

The international system is among the most foundational and contested concepts in the discipline of international relations. It refers, in its most general sense, to the pattern of interactions among states and other actors operating within an anarchic global political environment — an environment characterised by the absence of any supreme central authority above the level of the sovereign state. To understand international relations in any meaningful depth, one must first understand the structure, logic, and dynamics of the international system within which all international actors operate, compete, cooperate, and seek to advance their interests.

The concept of a system implies something more than a simple collection of individual states. It implies that the units — primarily sovereign states, but increasingly also international organisations, non-state actors, and other entities — stand in structured relationships with one another, that these relationships follow identifiable patterns, and that the system as a whole has properties that cannot be reduced to the characteristics of any single unit acting alone. When scholars speak of the international system, they mean precisely this structured totality: the overall framework of political, economic, legal, military, and normative relationships that governs how states and other international actors relate to and interact with one another.

The importance of the international system as a unit of analysis is one of the central contributions of structural realism, or neorealism, to the study of international relations. Scholars such as Kenneth Waltz argued that the structure of the international system — defined primarily by the distribution of power among the major states — is the most powerful explanatory variable in international politics. The anarchic structure of the system, in Waltz's view, generates certain recurring patterns of state behaviour — self-help, balance of power, security competition — regardless of the domestic characteristics of the states involved. This structural logic has been one of the most influential and debated ideas in international relations theory.

Yet the international system is not a static entity. It has undergone profound transformations over the course of history, from the fragmented, locally bounded political orders of antiquity through the European state system established at Westphalia in 1648 to the truly global international system of the twenty-first century. Each of these historical phases of the international system has had its own distinctive structure, characteristics, and dynamics, and understanding the historical evolution of the system is essential to understanding its current form and anticipating its future development.

1.1 Meaning of the International System

At its simplest, the international system can be defined as the totality of states and other significant actors interacting in the global arena, together with the structures, norms, and processes that govern those interactions. This definition captures three essential dimensions of the concept: the actors who constitute the system, the interactions that take place among them, and the structures and norms that shape and constrain those interactions. Each of these dimensions requires further elaboration.

The actors within the international system are, first and foremost, sovereign states — the primary legal and political units of the system, endowed with territorial integrity, internal sovereignty, and formal equality under international law. However, the roster of significant actors in the contemporary international system extends well beyond states to include intergovernmental organisations such as the United Nations, the World Trade Organisation, and regional bodies such as the African Union; non-governmental organisations (NGOs) engaged in advocacy, humanitarian work, and norm promotion; multinational corporations whose economic activities span multiple jurisdictions; transnational civil society networks; and, increasingly, powerful individual actors whose platforms and resources give them significant influence on international affairs.

The interactions that take place within the international system are extraordinarily diverse — encompassing diplomacy, trade, military competition, economic cooperation, cultural exchange, environmental negotiations, and countless other forms of inter-state and transnational activity. These interactions are not random: they follow patterns that reflect the interests, capabilities, and constraints of the actors involved, and that are shaped by the structural features of the system itself. Understanding these interaction patterns — their regularities, their drivers, and their consequences — is one of the central tasks of international relations theory.

The structures and norms that shape interactions within the international system include both formal institutions — international law, treaty regimes, international organisations — and informal norms and expectations that, while not legally binding, nonetheless exercise a powerful influence on state behaviour. The norm of state sovereignty, for example, is one of the most fundamental structural elements of the international system: it establishes the basic rule that states are entitled to exercise supreme authority within their own territory and are not subject to interference in their internal affairs by other states. This norm has been repeatedly challenged and tested, but it remains a central pillar of the international system's architecture.

1.2 Importance of the International System in IR Studies

The international system occupies a privileged position in the study of international relations because it provides the structural context within which all other phenomena of international politics must be understood. Just as social phenomena cannot be fully explained without reference to the social structures — institutions, norms, power relations — within which they occur, international phenomena cannot be fully explained without reference to the systemic context that shapes the interests, capabilities, and choices of states and other actors. A state's foreign policy, for example, cannot be understood purely in terms of its domestic politics and preferences: it must also be understood in terms of the systemic constraints and opportunities that the international environment presents.

Different theoretical traditions in international relations have emphasised different aspects of the international system. Realists have focused primarily on the distribution of power within the system, arguing that this structural feature is the primary determinant of state behaviour and international outcomes. Liberals have emphasised the role of international institutions and interdependence in mitigating the competitive dynamics of the anarchic system. Constructivists have highlighted the constitutive role of norms, identities, and ideas in shaping how actors understand themselves and their interests within the system. Each of these theoretical perspectives captures important insights about different dimensions of the international system, and a full understanding of the system requires engagement with all of them.

1.3 Evolution of the International System

The international system as we know it today is the product of a long historical evolution that has transformed both the actors and the structures of global politics. In ancient times, the political world was organised around regional orders — city-state systems, empires, and tribal confederacies — that had limited contact with one another and that lacked many of the features we associate with the modern international system. The concept of sovereignty, for example, was essentially unknown in the ancient world, where political authority was typically grounded in religious legitimacy, dynastic right, or military dominance rather than in the idea of territorially bounded legal supremacy.

The decisive turning point in the evolution of the international system is conventionally located in the Peace of Westphalia of 1648, which ended the Thirty Years' War in Europe and established, for the first time in systematic form, the principle that Europe was composed of sovereign states possessing equal legal standing and the right to conduct their own internal and external affairs without interference. The Westphalian settlement laid the foundations of the modern state system, and the principles it embodied — sovereignty, territorial integrity, non-interference — continue to define the basic architecture of the international system to the present day, even as they have been increasingly challenged and qualified in the contemporary era.

The subsequent evolution of the international system has been marked by several major transformations: the expansion of the European state system to encompass the entire globe through colonialism and later decolonisation; the emergence of international institutions and international law as increasingly significant elements of systemic structure; the experience of two world wars and the cold war, which dramatically reshaped the distribution of power and the institutional architecture of the system; and the contemporary transformations associated with globalisation, the rise of new powers, and the emergence of new transnational challenges. Each of these transformations has altered in important ways the structure, actors, and dynamics of the international system.

1.4 Components of the International System

The international system can be analysed in terms of several key components that together constitute its overall structure and dynamics. The first and most fundamental component is the set of actors who participate in the system — states, international organisations, non-state actors, and others whose activities and interactions constitute the substance of international life. The second component is the distribution of capabilities among these actors — the relative power, resources, and influence that different actors command, which shapes the hierarchy and structure of the system. The third component is the set of interactions that take place among actors — the flows of goods, capital, information, people, and ideas that cross borders, and the diplomatic, military, economic, and cultural transactions that characterise inter-state and transnational relations.

A fourth component is the normative and institutional framework of the system — the rules, norms, laws, and institutions that govern interactions among actors and that define the rights and obligations of states and other participants in the system. A fifth component, closely related to the normative framework, is the set of shared understandings and identities that shape how actors perceive their interests and understand their place in the system. These ideational components of the international system — emphasised by constructivist scholars — are not reducible to material power or institutional structure, but they play a crucial role in shaping how actors behave and how the system evolves.

1.5 Structure and Dynamics of Global Politics

The structure of global politics at any given moment reflects the distribution of power among the major actors in the international system, the institutional and normative framework that governs their interactions, and the ideational context that shapes their perceptions and identities. These structural features are not fixed: they change over time as the distribution of power shifts, as new institutions are created or old ones weakened, and as norms and ideas evolve. Understanding the structure of global politics means understanding both its relatively stable features — such as the anarchic character of the system and the norm of state sovereignty — and its dynamic features — such as the ongoing shifts in the balance of power associated with the rise of China and other emerging powers.

The dynamics of global politics — the processes by which the system evolves and changes — reflect the interaction of structure and agency. Structural forces — such as shifts in the distribution of power, the development of new technologies, and the emergence of new transnational challenges — shape the context within which actors make decisions and pursue their interests. But actors — states, international organisations, social movements, individual leaders — are not simply puppets of structural forces: they make choices, form coalitions, create institutions, and engage in ideational contestation that can in turn reshape the structural environment. The interplay between structure and agency is one of the central dynamics of the international system, and understanding it is essential to understanding how and why the system changes over time.

1.6 Overview of the Development of the International System

The remainder of this module traces the development of the international system through its major historical phases and examines its principal structural characteristics, the actors who operate within it, and the dynamics of power that shape its evolution. Section 2 examines the conceptual meaning of the international system, exploring the major scholarly definitions and theoretical frameworks through which it has been analysed. Section 3 traces the historical development of the system from ancient times to the post-Cold War era. Sections 4 and 5 examine the structure and characteristics of the international system in detail. Section 6 surveys the major actors within the system. Section 7 analyses the role of power in shaping systemic dynamics. Sections 8 and 9 examine contemporary changes and challenges facing the system. Sections 10 and 11 look forward to the future of the international system and offer concluding reflections.

2.0 Conceptual Meaning of the International System

The concept of the international system is used in a variety of ways across the international relations literature, reflecting different theoretical perspectives and different levels of analytical abstraction. Some scholars use the term primarily to refer to the overall distribution of power among states — emphasising the structural constraints that this distribution imposes on state behaviour. Others use it to refer to the full range of relationships and interactions among all international actors — emphasising the complexity and diversity of global political life. Still others use it to refer to the normative and institutional order that governs international relations — emphasising the role of rules, norms, and shared expectations in constituting the system and enabling social interaction among its members. This section examines these different conceptual approaches and their implications for the study of international relations.

2.1 Definitions of the International System

The variety of definitions of the international system in the scholarly literature reflects both the complexity of the phenomenon being described and the theoretical disagreements that have long characterised the discipline of international relations. Four definitions, each associated with a major scholar or theoretical tradition, illustrate the range of approaches that have been taken.

Kenneth Waltz, the founding figure of neorealism, defines the international system primarily in terms of its structure — the distribution of capabilities among states. For Waltz, the defining characteristic of the international system is its anarchic ordering principle: unlike domestic political systems, which are organised hierarchically under a sovereign authority, the international system is characterised by the absence of any supreme authority above the level of the state. This anarchic structure, combined with the distribution of capabilities among states, generates the fundamental dynamics of international politics — self-help, the balance of power, and the security dilemma. Waltz's definition is deliberately spare and abstract: it focuses on the structural features that, in his view, have the greatest explanatory power, while bracketing the enormous diversity of state characteristics, domestic politics, and specific issues that distinguish individual states and relationships.

Morton Kaplan, writing from a systems-theoretic perspective, defines the international system as a pattern of relations among states that can be characterised by a set of rules governing the behaviour of states within the system and a set of transformation rules describing how the system changes when its rules are violated or when its structure is disrupted. Kaplan identified six distinct types of international system — including the balance of power system, the loose bipolar system, the tight bipolar system, the universal system, the hierarchical system, and the unit veto system — each characterised by a distinctive pattern of behaviour rules and structural features. Kaplan's approach is more complex and typologically rich than Waltz's, but it has been criticised for being overly abstract and difficult to apply empirically.

Hedley Bull, writing from the perspective of the English School, defines the international system as a society of states — what he calls the 'anarchical society' — governed by common rules and institutions that states have created to manage their relations with one another. For Bull, the international system is not merely a mechanical system driven by power politics: it is a social system in which states share certain common interests and values, recognise common rules, and participate in common institutions. This emphasis on the social and normative dimensions of the international system distinguishes Bull's approach from that of the structural realists and provides the foundation for the English School's distinctive understanding of international order.

James Rosenau, writing from a transnationalist perspective, defines the international system as a network of global interactions that encompasses not only states but also a wide range of non-state actors — multinational corporations, international organisations, transnational social movements, and even individual citizens engaged in politically significant cross-border activities. Rosenau's 'turbulence model' of global politics emphasises the increasing complexity and fragmentation of the international system in the contemporary era, as the capacities and autonomy of non-state actors grow and as the ability of states to control cross-border flows declines. His approach anticipates many of the themes of contemporary globalisation theory and provides a useful counterpoint to the state-centric perspective of structural realists.

Table 1: Scholarly Definitions of the International System — Theoretical Traditions and Key Emphases

2.2 The International System as a Political Structure

The characterisation of the international system as a political structure is central to the neorealist approach associated with Kenneth Waltz. A structure, in Waltz's framework, is defined by three elements: an ordering principle, the differentiation of units, and the distribution of capabilities. In the international system, the ordering principle is anarchy — the absence of a central authority above the level of the state. The units of the system — states — are formally undifferentiated, in the sense that they all perform the same basic functions (governance, defence, economic management, etc.) even though they differ enormously in their capabilities. The distribution of capabilities — the relative power of states — is the key variable that determines the specific structure of the system at any given moment, distinguishing between unipolar, bipolar, and multipolar configurations.

The structural approach to the international system has the significant advantage of parsimony: it explains a great deal about international behaviour using a relatively small number of structural variables. The recurring patterns of international politics — the tendency of states to balance against dominant powers, the instability of hegemonic orders, the security dilemma that drives states into arms races and military competition — can all be explained, in structural realist terms, as consequences of the anarchic structure of the system and the distribution of capabilities within it, without recourse to detailed analysis of the domestic characteristics or specific preferences of individual states.

However, the structural approach has also been criticised for its excessive parsimony — for abstracting away from the very features of international life that are most interesting and important. Critics argue that the structural realist framework cannot adequately explain variation in state behaviour among states facing similar structural constraints, the role of ideas and norms in shaping state interests and behaviour, the significance of international institutions and international law, or the politics of non-state actors and transnational civil society. These criticisms have driven the development of alternative theoretical approaches — including liberal institutionalism, constructivism, and critical theory — that seek to incorporate the factors that structural realism brackets.

2.3 Systemic Interaction among States

The concept of systemic interaction captures the idea that the behaviour of states in the international system is not only determined by their own individual characteristics and preferences but is also shaped by their position within the system and their interactions with other states. Systemic interaction operates through a variety of mechanisms: strategic interaction, in which each state's decisions are affected by its expectations about how other states will respond; socialisation, in which states that participate in the international system come to adopt shared norms, identities, and practices through their interaction with other members; and diffusion, in which innovations — whether in military technology, economic organisation, political institutions, or normative standards — spread from one state to others through a variety of channels.

The significance of systemic interaction is one of the key arguments for treating the international system as a distinct level of analysis — above the level of the individual state — in the study of international relations. The unit-level analysis, which focuses exclusively on the characteristics and choices of individual states, necessarily misses the systemic effects that emerge from the interactions of multiple states within a structured environment. The security dilemma, for example, is a systemic phenomenon: it arises not from the aggressive intentions of any individual state but from the logic of interaction in an anarchic environment, where any state's efforts to improve its security by acquiring more military capability will be perceived as threatening by other states, leading to counter-armament that leaves all states less secure than before.

2.4 International System and Global Order

The concept of global order refers to the arrangements — formal and informal, institutional and normative, material and ideational — that provide a degree of stability, predictability, and regularity to international relations. Global order is not a synonym for peace or harmony: it simply means that international relations are conducted according to certain established patterns rather than in a condition of complete randomness or perpetual violent conflict. As Hedley Bull observed, order in international relations is consistent with a significant degree of conflict and competition among states: what distinguishes an ordered international system from a disorderly one is not the absence of conflict but the presence of shared rules and expectations that constrain how that conflict is conducted.

The relationship between the international system and global order is complex and mutually constitutive. The international system provides the structural context within which global order is created, maintained, and transformed. But global order — through international institutions, international law, and shared norms — also shapes the international system by constraining state behaviour, facilitating cooperation, and providing mechanisms for the peaceful management of disputes. The post-1945 liberal international order, anchored by the United Nations system, the Bretton Woods institutions, and an extensive network of international law and norms, represents a particularly ambitious attempt to create a stable and cooperative global order within the framework of the anarchic international system. The current challenges to this order — from revisionist powers, populist nationalism, and the strains of globalisation — represent a significant test of its resilience and adaptability.

2.5 Anarchy in the International System

Anarchy is the foundational structural condition of the international system — the absence of any supreme political authority above the level of the sovereign state with the power to make and enforce binding rules on all states. It is important to be clear about what the concept of international anarchy does and does not mean. It does not mean that international relations are characterised by constant chaos and violence — although it does mean that the threat of violence can never be entirely eliminated from inter-state relations. It does not mean that there are no rules or norms governing international behaviour — there are, and they are extensive and often effective. What it means, in essence, is that there is no international equivalent of a government — no supreme authority that can compel all states to obey international law, resolve disputes peacefully, or refrain from using force against one another.

The implications of international anarchy for state behaviour are a central subject of debate in international relations theory. For structural realists, anarchy is the primary driver of international competition and conflict: in the absence of any guarantee of security from above, states must rely on their own capabilities and on self-help strategies to ensure their survival. This logic of self-help generates the recurring patterns of international competition, arms racing, and balance-of-power politics that realists see as defining features of international life. For liberal institutionalists, anarchy is a constant but not a constraint that cannot be overcome: international institutions can mitigate the competitive dynamics of the anarchic system by creating mechanisms for coordination, building trust, reducing transaction costs, and providing information that enables states to cooperate more effectively.

2.6 The Role of Power Distribution

The distribution of power among states is, for structural realists, the single most important variable in explaining the behaviour and outcomes of the international system. The concept of power in international relations is multidimensional: it encompasses military capability, economic resources, technological capacity, diplomatic influence, and the ability to shape the preferences and behaviour of other actors through attraction and persuasion. The distribution of these forms of power among states determines the hierarchy of the international system — identifying the great powers, the middle powers, and the small states that constitute the system's membership — and shapes the specific dynamics of competition and cooperation that characterise international politics at any given moment.

Different distributions of power are associated with different structural configurations of the international system. A unipolar distribution — in which a single state possesses a preponderance of power that no coalition of other states can effectively challenge — is associated with a distinctive set of systemic dynamics, including debates about the sustainability of hegemony, the possibilities for hegemonic leadership in creating international order, and the responses of secondary states to the dominant power. A bipolar distribution — in which power is concentrated in two roughly equal superpowers — is associated with the relatively stable but deeply competitive dynamics of the Cold War. A multipolar distribution — in which power is more evenly distributed among several major states — is associated with a more complex and in some respects more dangerous balance-of-power politics, in which miscalculation and misperception are more likely.

3.0 Historical Development of the International System

The international system, as a structured global order of interacting political units, is a relatively recent historical phenomenon. While political interactions between different communities, kingdoms, and empires have existed since the earliest civilisations, the systematically organised, universal international system that we study in international relations theory — characterised by sovereign statehood, formal legal equality, and an extensive framework of international institutions and law — emerged only in the seventeenth century and became genuinely global only in the twentieth century. This section traces the major historical phases through which the international system has evolved, from the regional political orders of antiquity to the complex, globalised system of the contemporary era.

3.1 Ancient International Systems

The ancient world was home to a number of distinct regional political systems that shared some features with the modern international system but differed from it in fundamental respects. In ancient Greece, the system of city-states — poleis — that existed from approximately the eighth to the fourth centuries BCE constitutes the most extensively studied ancient analogue of the modern international system. The Greek city-state system exhibited several features that are recognisable from the perspective of modern international relations: a plurality of formally sovereign units, regular diplomatic interaction (including the institution of the proxenos, a resident representative in foreign cities), the use of international arbitration to settle disputes, the formation of alliances and the operation of balance-of-power dynamics, and the development of norms and rules governing warfare.

The ancient Near East provides another significant example of a regional international system. From approximately the sixteenth to the twelfth centuries BCE, the great powers of the ancient Near East — Egypt, Hatti (the Hittite Empire), Babylon, Assyria, and Mittani — engaged in a complex system of diplomacy, alliance formation, treaty negotiation, and trade that bears many resemblances to modern international relations. The archives of Amarna, discovered in Egypt in the nineteenth century, contain extensive diplomatic correspondence between the Egyptian pharaoh and other rulers of the ancient Near East, demonstrating the existence of sophisticated diplomatic practices including formal treaties, royal marriages as instruments of alliance, and detailed protocols for diplomatic communication.

Ancient China provides a third major example of a regional international system — the Warring States period (approximately 475–221 BCE) — in which a number of rival kingdoms competed for supremacy, forming alliances, developing sophisticated military technologies and strategies, and engaging in diplomatic negotiations that produced a rich body of political thought about interstate relations. The Chinese Warring States system is particularly interesting because it ultimately ended with the unification of China under the Qin dynasty — a transformation that is sometimes cited as an illustration of the logic of hegemonic domination and systemic transformation.

However, these ancient regional systems differed from the modern international system in crucial respects. They were regional rather than global in scope — the Greek city-state system had no significant interaction with the contemporary political systems of India or China. They lacked the concept of sovereignty as we understand it — the idea that each state possesses supreme authority within its own territory, equal legal standing with all other states, and the right to non-interference in its internal affairs. And they were eventually subsumed by empires — the Macedonian empire, the Roman empire, the Qin empire — that abolished the pluralism of the system and imposed a hierarchical order rather than a system of formally equal units.

3.2 Medieval Political Order

The medieval period in European history (approximately the fifth to the fifteenth centuries CE) presents a political order fundamentally different from both the ancient city-state systems and the modern international system. Medieval Europe was characterised by a complex, overlapping, and hierarchical system of political authority — the feudal order — in which sovereignty was not concentrated in the hands of territorial states but was distributed among a multiplicity of political entities: kingdoms, principalities, city-states, church institutions, and the Holy Roman Empire, all of which exercised overlapping forms of authority over particular territories and populations.

The defining feature of the medieval order was the dual authority of the pope and the Holy Roman Emperor — the twin pillars of universal authority that, at least in theory, transcended the particularism of individual kingdoms and principalities. In practice, the relationship between papal and imperial authority was one of constant tension and conflict, as popes and emperors competed for supremacy and as individual rulers sought to expand their autonomy at the expense of both. The Investiture Controversy of the eleventh and twelfth centuries, the conflicts between popes and emperors over the boundaries of their respective spheres of authority, and the eventual weakening of both universal powers in the fourteenth and fifteenth centuries all contributed to the gradual emergence of the territorial state as the primary unit of political authority.

The medieval order also lacked the concept of sovereignty as it would later be developed in the Westphalian era. Authority in medieval Europe was personal rather than territorial — it was exercised by lords over persons rather than over bounded territories — and it was legitimated by reference to divine will and natural law rather than to the secular principle of supreme territorial authority. The development of the modern concept of sovereignty, which would define the post-Westphalian international system, required a fundamental transformation in the conceptual foundations of political authority — a transformation that was facilitated by the Renaissance, the Reformation, and the violent religious conflicts of the sixteenth and seventeenth centuries.

3.3 The Westphalian International System

The Peace of Westphalia of 1648, which ended the Thirty Years' War and the Eighty Years' War, is conventionally regarded as the founding moment of the modern international system. The two treaties that constituted the Westphalian settlement — the Treaty of Osnabrück and the Treaty of Münster — established, for the first time in systematic form, a set of principles that would define the architecture of the international system for the next four centuries: the sovereignty of states, the territorial integrity of states, the principle of non-interference in the internal affairs of other states, and the formal legal equality of states in their mutual relations.

The Westphalian system represented a decisive break with the medieval order in several important respects. It established the territorial state — defined by fixed boundaries and exercising supreme authority within those boundaries — as the primary unit of the international system, replacing the overlapping, hierarchical authority structures of the medieval order. It relegated religious authority — previously a major source of political legitimacy and a driver of political conflict — to the domestic sphere, establishing the principle (cuius regio, eius religio — 'whose realm, his religion') that each ruler had the right to determine the religion of his own territory without external interference. And it established the basis for a system of diplomatic relations among formally equal sovereign states, laying the foundations for the norms and institutions of modern diplomacy.

The subsequent development of the Westphalian system through the seventeenth, eighteenth, and nineteenth centuries was marked by the elaboration of international law, the development of formal diplomatic institutions, the emergence of the great power concert as a mechanism for managing the system, and the gradual expansion of the system beyond its European origins. The Congress of Vienna of 1815, which restructured the European order after the Napoleonic Wars, was a landmark in the development of the Westphalian system: it established the Concert of Europe as a mechanism for great power coordination, created the first modern international conference system, and demonstrated the possibility of managing systemic transformation through multilateral diplomacy rather than hegemonic imposition.

3.4 Colonial International System

The expansion of the European state system through colonialism fundamentally transformed the international system by extending it from its European origins to encompass the entire globe — but doing so through a profoundly asymmetrical process that denied the non-European peoples and political entities the sovereignty and formal equality that the Westphalian system accorded to European states. European colonialism, which reached its apogee in the late nineteenth and early twentieth centuries, involved the conquest and subjugation of vast territories in the Americas, Africa, Asia, and Oceania, the imposition of European political and legal systems, the extraction of resources and labour, and the violent disruption of pre-existing political, social, and cultural orders.

The colonial international system operated on a logic of hierarchical difference rather than formal equality. The European states, which constituted the 'civilised' core of the system, were accorded full sovereignty and the rights and obligations of international law. Colonial territories, by contrast, were treated as the property of their colonising powers and their inhabitants as lacking the political standing to be full members of the international system. This hierarchical structure was codified in international law through doctrines such as the standard of civilisation — which held that only states that met a European-defined standard of 'civilisation' were entitled to full recognition as sovereign members of the international community — and the concept of terra nullius — which held that territories not occupied by 'civilised' peoples could be lawfully claimed by European powers.

The decolonisation that followed the Second World War — primarily concentrated in the period from the late 1940s to the mid-1970s — fundamentally transformed the international system by dramatically expanding its membership and challenging the hierarchical principles on which the colonial order had been based. The emergence of dozens of newly independent states in Africa, Asia, and the Caribbean brought new voices and perspectives into the international system, challenged the dominance of the Western powers, and gave rise to new political movements — including the Non-Aligned Movement and the push for a New International Economic Order — that sought to reshape the system in ways more favourable to the interests of the developing world.

For African states, including South Sudan, the legacy of colonialism continues to shape the international system in profound ways. The borders inherited from colonial rule — drawn by European powers with little regard for pre-existing African political or ethnic boundaries — continue to generate tensions and conflicts. The economic structures created by colonialism — oriented towards the export of raw materials to European markets — continue to shape the economic vulnerabilities of many African states. And the international institutions and legal frameworks created primarily by and for the benefit of the Western powers continue to be sites of contestation over the distribution of power and influence within the system.

3.5 The Cold War International System

The Cold War international system, which dominated global politics from approximately 1947 to 1991, was defined by a fundamental bipolar structure — the division of the international system into two competing blocs organised around the two superpowers, the United States and the Soviet Union. The bipolar structure of the Cold War system was unprecedented in the history of international relations: never before had the international system been so completely dominated by the competition between two roughly equal superpowers, each commanding the loyalty (willing or unwilling) of a large number of client and aligned states, each possessing nuclear arsenals of sufficient destructive power to destroy human civilisation, and each committed to a fundamentally different vision of political and economic organisation.

The bipolar structure of the Cold War system generated a distinctive set of systemic dynamics. The nuclear balance of terror — the mutual assurance that any nuclear attack would be met with a devastating retaliatory strike — created what some scholars have called the 'long peace': a period of remarkable stability in direct military conflict between the two superpowers, even as their competition manifested itself in proxy wars, arms races, ideological competition, and interventions in the developing world. The stability of the bipolar structure — its predictability and the clarity of the alliance commitments on each side — has been contrasted favourably by some scholars, particularly structural realists, with the greater instability of multipolar systems.

Africa was profoundly affected by the Cold War international system. Many African states that gained independence in the 1950s and 1960s found themselves immediately drawn into the superpower competition, with both the United States and the Soviet Union actively seeking to extend their influence through aid, arms sales, military assistance, and support for particular political factions. The consequences for African political development were often deeply damaging: Cold War strategic considerations frequently led the superpowers to support authoritarian regimes that served their strategic interests, regardless of their human rights records or development performance, and the proxy conflicts funded and armed by the superpowers caused enormous suffering in countries such as Angola, Mozambique, Ethiopia, and the Horn of Africa — a region of direct relevance to South Sudan's own history.

3.6 Post–Cold War Global Order

The end of the Cold War, marked symbolically by the fall of the Berlin Wall in November 1989 and concluded formally by the dissolution of the Soviet Union in December 1991, represented the most profound structural transformation of the international system since the end of the Second World War. The collapse of the Soviet Union eliminated the bipolar structure that had defined the Cold War system and created, at least temporarily, a unipolar international order dominated by the United States as the world's sole remaining superpower. This 'unipolar moment' — as the analyst Charles Krauthammer described it — was characterised by a level of American preponderance in military, economic, and soft power that had no precedent in modern international history.

The post-Cold War period was initially marked by considerable optimism about the prospects for a new liberal international order — one in which the spread of democracy and market economies, the deepening of international institutions, and the management of global challenges through multilateral cooperation would create a more peaceful and prosperous world. This optimism was reflected in the remarkable expansion of international institutions and treaty regimes in the 1990s, the proliferation of peacekeeping operations, the development of international criminal justice mechanisms, the consolidation of the European Union, and the deepening of economic globalisation.

However, the optimism of the early post-Cold War period proved to be short-lived. The first decade of the twenty-first century was marked by the shock of the September 11, 2001 terrorist attacks, the controversial American-led invasions of Afghanistan and Iraq, the resurgence of great-power competition as Russia reasserted its influence and China's rise accelerated, and the financial crisis of 2008 that exposed fundamental weaknesses in the global economic order. These developments challenged the narrative of a triumphant liberal international order and raised new questions about the durability of the unipolar moment and the direction of systemic change.

Table 2: Historical Phases of the International System — Characteristics, Actors, and Dominant Logic

4.0 Structure of the International System

The structure of the international system refers to the underlying framework of relationships, principles, and power distributions that shape how states and other actors interact within the global political environment. Understanding systemic structure is essential to understanding why states behave as they do and why the international system as a whole exhibits the patterns it does — including the recurrence of balance-of-power dynamics, the formation of alliances, the tendency of dominant powers to provoke counter-balancing coalitions, and the periodic transformation of the system when its structural parameters change. This section examines the concept of system structure, the main types of structural configuration identified in the literature, and the implications of different structural forms for stability and state behaviour.

4.1 Meaning of System Structure

As discussed in Section 2, Waltz's concept of international system structure rests on three elements: ordering principle, differentiation of units, and distribution of capabilities. The ordering principle of the international system is anarchy — the absence of any supreme authority above the level of the state. The units of the system — states — are functionally undifferentiated, in the sense that they all perform the same basic governmental functions even as they differ enormously in size, wealth, and power. The distribution of capabilities — how power is distributed among states — is the variable element that distinguishes different structural configurations.

It is important to note that Waltz's concept of structure is deliberately abstract and minimalist. He deliberately excludes from the definition of structure all aspects of the relationships between states — their alliances, their histories of conflict and cooperation, their shared norms and institutions — restricting structure to the pure distribution of capabilities. This minimalist approach maximises the parsimony of structural analysis but at the cost of excluding many features of the international environment that have significant effects on state behaviour. Critics have argued that Waltz's concept of structure is too thin to do the explanatory work he asks of it, and have proposed richer conceptions of structure that incorporate norms, institutions, and ideational factors.

An alternative conception of international system structure, associated with scholars in the English School and constructivist traditions, understands structure in a broader sense to include the normative and institutional framework of international society. On this view, the structure of the international system encompasses not only the distribution of material capabilities but also the shared norms, rules, and institutions that define the basic terms of interaction among states — including the norms of sovereignty and non-interference, the rules of international law, the procedures of multilateral institutions, and the shared understandings about what constitutes legitimate behaviour in international relations. This broader conception of structure is better able to explain how international institutions and norms constrain and shape state behaviour, but it sacrifices the parsimony of the structural realist approach.

4.2 Distribution of Power in the System

The distribution of power among states is the central variable in structural analyses of the international system. Power in international relations is a complex and multidimensional concept. The classic realist conception focuses primarily on military capability — the ability to coerce, deter, or defeat other states through the use or threat of armed force. A broader conception of power, associated with scholars such as Joseph Nye and Robert Keohane, recognises that economic resources, technological capacity, and the ability to set the international agenda — what Nye calls 'soft power' — are also important dimensions of power that shape a state's ability to influence outcomes in the international system.

The distribution of power in the contemporary international system is a matter of considerable debate. At the military level, the United States continues to maintain a degree of preponderance that no other state can match: its defence spending exceeds that of the next several states combined, it maintains a global network of bases and alliances that no other state approaches, and its technological capabilities in key areas such as precision strike, intelligence, surveillance, and reconnaissance are without peer. However, the economic dimension of power has become increasingly important, and here the picture is more contested: China's rapid economic growth has made it the world's second largest economy, and on some measures of purchasing power parity it has already surpassed the United States.

For smaller and developing states, the distribution of power in the international system defines the structural constraints within which they must operate. Small states cannot compete militarily with the great powers and must therefore rely on diplomatic skill, alliance membership, multilateral engagement, and the protection afforded by international law and norms to safeguard their interests and sovereignty. Understanding the distribution of power in the system and the implications of that distribution for their own security and development is therefore a crucial element of the foreign policy analysis of states like South Sudan.

4.3 Types of System Structures

International relations theory distinguishes three main types of international system structure, defined by the number of great powers in the system: unipolarity, bipolarity, and multipolarity. Each structural configuration is associated with a distinctive set of dynamics, stability properties, and patterns of state behaviour.

A unipolar system is one in which a single state — the hegemon — possesses such a preponderance of power that no other state or coalition of states can effectively challenge it. Historical examples of near-unipolarity include the position of Rome in the Mediterranean world of the second and first centuries BCE, the dominance of Britain in global affairs in the mid-nineteenth century, and the position of the United States in the immediate post-Cold War period. Unipolar systems raise important questions about the sustainability of hegemony, the behaviour of secondary states in response to preponderant power, and the conditions under which balancing coalitions might emerge to challenge the hegemon.

A bipolar system is one in which power is concentrated in two roughly equal great powers. The Cold War international system, characterised by the competition between the United States and the Soviet Union, is the canonical modern example of bipolarity. Structural realists have debated the stability properties of bipolar systems at length: some, like Waltz, have argued that bipolarity is more stable than multipolarity because it reduces the risks of miscalculation and simplifies alliance commitments; others have argued that the rigid confrontation of two heavily armed superpowers creates its own distinctive risks of escalation and catastrophic conflict.

A multipolar system is one in which power is distributed among several major powers — typically taken to mean five or more great powers of roughly comparable capabilities. The nineteenth-century European state system, governed by the Concert of Europe after 1815, is often cited as the archetypal example of multipolarity. Contemporary analysis of the international system increasingly suggests that the unipolar moment of the 1990s is giving way to a more multipolar configuration, as the relative power of the United States declines and the capabilities of China, India, Russia, Brazil, and other emerging powers grow. Many scholars argue that the twenty-first century is likely to be characterised by a complex, contested multipolarity that presents new challenges for international stability and governance.

Table 3: Types of International System Structures — Definitions, Examples, Stability, and Key Dynamics

4.4 Structural Constraints on State Behavior

One of the central claims of structural approaches to international relations is that the structure of the international system exercises a powerful constraining effect on state behaviour, limiting the range of choices available to states and generating certain recurring patterns regardless of the specific preferences, ideologies, or domestic politics of the states involved. The anarchic structure of the system, in particular, is held to generate the logic of self-help — the imperative for each state to rely primarily on its own capabilities to ensure its security — and the balance-of-power dynamics that this logic produces.

The structural constraint argument is perhaps most compelling in relation to the security behaviour of states. In an anarchic system, no state can be fully confident in the security guarantees of others — promises and alliances may be broken, and the interests of other states may diverge from one's own. This uncertainty generates the security dilemma: any state that increases its military capabilities in order to enhance its own security will be perceived as threatening by other states, who will respond by increasing their own capabilities, leaving all states less secure than before despite having invested more in security. The structural logic of the security dilemma operates regardless of the intentions of the states involved — even purely defensive military buildups can trigger counterproductive action-reaction spirals.

However, structural constraints are not absolute determinants of state behaviour. States facing similar structural constraints often behave differently, reflecting variation in their domestic politics, ideologies, leadership, and strategic cultures. Alliance choices, for example, are constrained by the structural distribution of power but are not determined by it: states have considerable latitude in choosing their alliance partners, and different states facing the same structural circumstances will often make different alliance choices. The claim of structural theory is not that structure determines behaviour in every specific case but that it sets the background conditions and generates the most powerful pressures that shape patterns of behaviour across the system over time.

4.5 Stability and Instability in System Structures

The question of which type of international system structure is most stable — most conducive to peace and the absence of major systemic war — is one of the most important and debated questions in international relations theory. As noted above, structural realists such as Waltz have argued for the relative stability of bipolarity, citing the simplicity of the deterrence calculation, the clarity of alliance commitments, and the absence of the dangerous miscalculations that can occur in more complex multipolar systems. Others, including scholars associated with the power transition theory developed by A.F.K. Organski, have argued that unipolarity — or more precisely, a hierarchical system in which a dominant power is supported by a coalition of satisfied secondary states — is the most stable configuration, because it eliminates the competition among roughly equal powers that historically has generated the most destructive systemic wars.

Power transition theory, developed by Organski and later elaborated by scholars such as Ronald Tammen, argues that the most dangerous moments in the international system are those in which a rising power approaches the capabilities of the dominant power and challenges the legitimacy of the existing international order. The theory predicts that the risk of major war is highest when a dissatisfied rising power reaches rough parity with the dominant power and is willing to challenge the status quo. Applied to the contemporary international system, power transition theory suggests that the rise of China — a revisionist power challenging the American-led liberal international order — represents precisely the kind of dangerous power transition that has historically been associated with systemic conflict.

4.6 System Transformation

System transformation refers to fundamental changes in the structure, character, or membership of the international system that alter its basic parameters — shifts that go beyond normal fluctuations within a stable structural framework. Major systemic transformations in the history of the international system include the transition from the medieval order to the Westphalian system, the transformation produced by the two world wars and the collapse of European hegemony, the bipolar transformation of the Cold War, and the post-Cold War transition to what appears to be an emerging multipolar order.

Systemic transformations can occur through several different mechanisms. Hegemonic war — a conflict of sufficient scale to transform the distribution of power and the institutional order of the system — is the most dramatic mechanism of systemic change, as exemplified by the Napoleonic Wars, the First World War, and the Second World War. Gradual power transitions — in which rising powers accumulate capabilities over decades and eventually challenge the position of the dominant power without necessarily triggering a hegemonic war — represent a potentially less violent but no less significant mechanism of systemic change. Institutional design — the deliberate creation of new international institutions and legal frameworks — represents a third mechanism of systemic change, one that has been particularly important in the post-1945 period. And normative change — the evolution of shared norms, values, and understandings that constitute the ideational basis of the system — represents a fourth mechanism, one that constructivist scholars emphasise.

5.0 Characteristics of the International System

The international system exhibits a number of characteristic features that distinguish it from other types of political system and that shape the behaviour of the actors operating within it. These characteristics reflect both the structural architecture of the system — its anarchic ordering principle, the formal equality of states, and the distribution of capabilities — and the normative and institutional framework that has evolved to manage the competitive dynamics that anarchic structure generates. Understanding these characteristics is essential to understanding why international politics has the distinctive features it does — why states arm themselves, why they form alliances, why they sometimes cooperate and sometimes conflict, and why international institutions, despite their limitations, play an important role in the management of international relations.

5.1 Anarchy and Lack of Central Authority

As discussed in earlier sections of this module, anarchy — the absence of any supreme authority above the level of the sovereign state — is the foundational structural characteristic of the international system. This anarchic condition distinguishes the international system from domestic political systems, in which a sovereign authority — the state — possesses the power to make and enforce law, adjudicate disputes, and maintain public order. In the international system, no such central authority exists: decisions about war and peace, the terms of economic exchange, the rules of the international order, and the resolution of disputes ultimately depend on the consent, coercion, or coordinated action of the states themselves.

The implications of anarchy for the management of international relations are profound. In the absence of a world government capable of enforcing international law and deterring aggression, states must maintain their own military capabilities to deter potential adversaries and defend their interests. They must rely on their own judgment about when and how to use force, limited by the norms of international law but not effectively constrained by any external enforcement authority. They must negotiate the terms of international cooperation without the benefit of a central authority that can guarantee the performance of agreements — a challenge that has given rise to elaborate mechanisms for credible commitment, monitoring, and enforcement in international law and institutions.

It is important to note, however, that anarchy in the international system does not mean the complete absence of order. As Hedley Bull and the English School have emphasised, the international system has developed an extensive array of norms, rules, and institutions that provide a significant degree of order even in the absence of a central authority. The norm of state sovereignty, the rules of diplomatic protocol, the laws of war, international trade rules, and the procedures of international organisations all contribute to the orderliness of international relations without requiring a world government to enforce them. The existence of this normative and institutional framework does not eliminate the anarchic character of the system, but it significantly modifies the pure competitive logic that anarchy might otherwise generate.

5.2 Sovereign Equality of States

Formal sovereign equality — the principle that all states, regardless of their size, wealth, or military power, possess equal legal standing in the international system — is one of the foundational norms of the international legal and political order. The principle is enshrined in Article 2(1) of the United Nations Charter, which provides that the Organisation 'is based on the principle of the sovereign equality of all its Members'. In practice, of course, states are profoundly unequal in their capabilities, resources, and influence, and the formal equality of the legal framework coexists with a steep hierarchy of actual power and influence. Nevertheless, the norm of sovereign equality has important practical implications: it gives every state, however small, an equal vote in the United Nations General Assembly; it entitles every state to the protections of international law; and it establishes the principle that the interests and rights of all states deserve consideration in the international order.

The tension between formal sovereign equality and actual power inequality is one of the central tensions of the international system. The permanent member status and veto power of the five permanent members of the UN Security Council — the United States, Russia, China, France, and the United Kingdom — is the most prominent institutional expression of this tension, formally entrenching the privileges of the five states that possessed the greatest power at the end of the Second World War. Demands for reform of the Security Council to better reflect the contemporary distribution of power — and to give representation to major emerging powers such as India, Brazil, Germany, Japan, and African states — are among the most contested issues in contemporary debates about international institutional reform.

5.3 Competition for Power and Security

Competition for power and security among states is one of the most persistent and distinctive features of the international system. In the anarchic international environment, states cannot rely on any central authority to guarantee their security: they must ultimately depend on their own capabilities — military, economic, diplomatic — and on the credibility of their alliance commitments to deter potential adversaries and protect their vital interests. This imperative for self-help in the provision of security generates a persistent competitive dynamic in the international system, driving states to invest in military capabilities, to form alliances, and to seek strategic advantages over potential rivals.

The competition for power and security in the international system takes multiple forms. Military competition involves the ongoing contest among states to develop and maintain military capabilities — armies, navies, air forces, nuclear weapons, intelligence systems, and increasingly cyber capabilities — that can deter potential adversaries and prevail in conflict if deterrence fails. Economic competition involves the pursuit of national economic advantage in international markets — through trade policy, industrial policy, investment strategy, and the management of international economic institutions. Diplomatic competition involves the contest for influence, prestige, and favourable alignments in the international arena — through the cultivation of bilateral relationships, the management of multilateral coalitions, and the projection of soft power through cultural and public diplomacy.

For developing states, competition for power and security takes on a distinctive character. Unable to compete with the great powers in military and economic terms, developing states must rely primarily on diplomatic strategies — the cultivation of strategic partnerships, active engagement in multilateral institutions, and the use of international law and norms as levers of influence — to protect their interests and sovereignty. The experience of African states, including South Sudan, illustrates both the challenges and the opportunities that this diplomatic approach to security presents: the limited military and economic capabilities of most African states make them vulnerable to external pressure and internal conflict, but the norms of state sovereignty and non-interference, and the institutional framework of the African Union, provide some degree of protection.

5.4 Interdependence among States

Interdependence — the condition in which the actions and policies of states significantly affect one another, creating mutual sensitivity and vulnerability — is an increasingly important characteristic of the contemporary international system. The concept of interdependence gained particular prominence in the work of Robert Keohane and Joseph Nye, who argued in their landmark 1977 work Power and Interdependence that the growing density of economic, social, and political ties among states was fundamentally transforming the logic of international relations. Complex interdependence — characterised by multiple channels of interaction, the absence of a clear hierarchy among issues, and the declining role of military force as an instrument of policy — creates an international environment in which the pure realist logic of power politics is significantly modified by the costs and constraints that interdependence imposes.

Economic interdependence is the most visible and extensively studied form of inter-state interdependence. The dramatic expansion of international trade and investment since the Second World War — accelerated by the liberalisation of international economic regimes under the General Agreement on Tariffs and Trade (GATT) and its successor, the World Trade Organisation (WTO), and by the technological revolution in transport and communications — has created a degree of economic integration among national economies that was unprecedented in previous history. This integration creates both opportunities and vulnerabilities: states that participate in global markets can access larger markets, more diverse sources of supply, and the productivity gains of specialisation and economies of scale; but they also become vulnerable to disruptions in global supply chains, financial contagion, and the economic policies of trading partners.

5.5 Role of International Norms and Institutions

International norms and institutions play an essential role in the functioning of the international system, providing the normative and organisational infrastructure through which states coordinate their behaviour, manage their disputes, and cooperate on matters of common concern. The significance of norms and institutions in international relations has been one of the central points of contestation between realist and liberal perspectives in international relations theory. Realists, particularly structural realists, tend to view international institutions as reflections of the underlying distribution of power, with limited independent effect on state behaviour. Liberals and institutionalists, by contrast, argue that institutions have significant autonomous effects — that they change the incentive structures facing states, reduce transaction costs, provide information that enables cooperation, and create channels of communication that reduce the risk of conflict.

The post-1945 international institutional order — the United Nations, the Bretton Woods institutions, the GATT/WTO system, the International Court of Justice, and the extensive network of specialised agencies and treaty regimes — represents the most ambitious attempt in history to create a rule-based international order that can manage the competitive dynamics of the anarchic international system through institutions rather than through the pure play of power. This institutional framework has been imperfect and contested, but it has contributed significantly to the management of international relations over the past seven decades, facilitating an unprecedented expansion of international trade and investment, managing numerous potential conflicts through diplomatic mechanisms, and providing platforms for multilateral cooperation on global challenges.

5.6 Cooperation and Conflict

Cooperation and conflict are both inherent features of the international system, reflecting the simultaneous presence of common interests and conflicting interests among states. The anarchic structure of the system creates persistent incentives for competition and conflict — for self-help, arms racing, and the pursuit of relative gains at the expense of other states. But states also have significant common interests — in the maintenance of international order, the expansion of trade, the management of environmental challenges, and many other areas — that create powerful incentives for cooperation. The international system is therefore simultaneously a competitive arena and a framework for cooperation, and understanding the dynamics of both is essential to understanding how the system functions.

The conditions under which cooperation emerges and is sustained in the anarchic international system is one of the central questions of international relations theory. The prisoner's dilemma — a game-theoretic model in which rational individual choices lead to collectively suboptimal outcomes — is often used to illustrate the challenge of cooperation in the absence of a central authority that can enforce agreements. The key findings of research on international cooperation — including the importance of repeated interaction in enabling the development of trust and reciprocity, the role of international institutions in providing monitoring and enforcement mechanisms, and the significance of shared norms and identities in reducing the perceived costs of cooperation — have important implications for the design of international institutions and for the management of global challenges that require cooperative responses.

Table 4: Major Characteristics of the International System — Descriptions, Theoretical Perspectives, and Practical Implications

6.0 Actors within the International System

The international system is populated by a diverse and growing array of actors — entities whose activities and interactions constitute the substance of international life and whose interests, capabilities, and choices shape the system's dynamics. While sovereign states remain the primary actors in the international system — the fundamental units of the Westphalian order, the primary subjects of international law, and the principal decision-makers on questions of war, peace, and international governance — the contemporary system is characterised by the growing significance of a wide range of non-state actors whose roles and capabilities have expanded dramatically over the past several decades. This section examines the major categories of actors in the international system and analyses their respective roles, capabilities, and interactions.

6.1 States as Core Actors

States are the primary actors in the international system — the principal legal subjects of international law, the main decision-making units on questions of security and international order, and the organisational framework within which most political, economic, and social life is governed. The modern state is defined by a combination of characteristics: a permanent population, a defined territory, a government exercising effective control over the territory and population, and the capacity to enter into relations with other states — the criteria established by the 1933 Montevideo Convention on the Rights and Duties of States. The modern state system encompasses approximately 195 recognised sovereign states, ranging from the great powers that dominate the distribution of capabilities to the smallest island states whose populations number in the thousands.

The centrality of states in the international system reflects both their capabilities and their legitimacy. States command the most significant concentrations of material resources in the international system — the largest militaries, the largest economies, the most extensive administrative and diplomatic infrastructures. They also possess the unique legitimacy of sovereign authority — the internationally recognised right to govern their territory and population, to enter into binding international agreements, and to participate in the institutions of international governance. This combination of capability and legitimacy gives states a structural primacy in the international system that no other type of actor currently challenges, even as the capabilities and influence of non-state actors continue to grow.

However, states are not monolithic actors. They are complex political entities whose foreign policies are the product of domestic political processes — the bargaining among bureaucratic agencies, interest groups, political parties, legislatures, and civil society that shapes how governments define and pursue their interests in the international arena. Domestic politics — elections, institutional arrangements, ideological currents, and the influence of particular interest groups — can significantly affect the foreign policy choices of states, sometimes in ways that depart substantially from what a pure structural analysis would predict. This point is emphasised by scholars in the liberal and constructivist traditions, who argue that a full explanation of state behaviour must incorporate both systemic and domestic-level variables.

6.2 International Organizations

International organisations are formal, treaty-based institutions created by states to facilitate cooperation on matters of common concern. They range from the United Nations, the universal membership organisation at the apex of the international institutional system, to highly specialised technical bodies dealing with specific functional areas such as civil aviation, telecommunications, or atomic energy. The post-1945 period has witnessed an extraordinary proliferation of international organisations, reflecting the growing recognition that many international challenges — from trade and finance to public health and environmental protection — require institutionalised cooperative responses rather than purely bilateral management.

The United Nations remains the central institution of the international system, providing a universal forum for interstate diplomacy, a framework for the maintenance of international peace and security through the Security Council and peacekeeping operations, a system for the codification and progressive development of international law, and a platform for multilateral cooperation on development, human rights, and global challenges. The UN system encompasses not only the core UN organs — the General Assembly, Security Council, Secretariat, International Court of Justice, and the Economic and Social Council — but also a network of specialised agencies, funds, and programmes — including the World Health Organisation, the International Labour Organisation, the Food and Agriculture Organisation, UNICEF, the UNHCR, and many others — each dealing with specific areas of international cooperation.

Regional international organisations have also become increasingly important actors in the contemporary international system. The African Union (AU), the European Union (EU), the Association of Southeast Asian Nations (ASEAN), the Organisation of American States (OAS), and the Arab League all play significant roles in regional governance, conflict management, and the promotion of regional integration. For African states including South Sudan, the African Union and its sub-regional bodies — particularly the Intergovernmental Authority on Development (IGAD), which has been closely involved in South Sudanese peace processes — are among the most directly relevant international organisations for the management of security and development challenges.

6.3 Non-State Actors

Non-state actors — entities other than sovereign states that participate in international relations — have become increasingly prominent and influential in the contemporary international system. The category of non-state actors is extraordinarily diverse, encompassing international non-governmental organisations (INGOs) such as Amnesty International, Médecins Sans Frontières, and Oxfam; transnational advocacy networks that link activists and organisations across borders in pursuit of shared normative goals; global media organisations and news networks; religious organisations and movements; and, in a darker dimension, transnational criminal organisations and terrorist networks that operate across borders and challenge state authority.

The growing significance of non-state actors in international relations reflects several structural trends of the contemporary era. The communications revolution — the internet, social media, and other digital technologies — has dramatically reduced the barriers to transnational organisation and communication, enabling non-state actors to coordinate across borders, mobilise public opinion internationally, and engage with international institutions in ways that were previously impossible. The deepening of globalisation has created new transnational civil society networks that cut across national boundaries and create new forms of transnational political identity and advocacy. And the increasing complexity of the international agenda — with issues such as human rights, environmental protection, global health, and humanitarian action requiring expertise and moral authority that non-state actors can often provide — has given non-state actors new roles and influence in international governance.

6.4 Multinational Corporations

Multinational corporations (MNCs) — firms that operate productive facilities in more than one country — are among the most economically significant actors in the contemporary international system. The largest MNCs — including companies such as Apple, Amazon, Saudi Aramco, Microsoft, and Walmart — command revenues and assets that rival or exceed those of many sovereign states. Their decisions about where to locate production, how to manage global supply chains, whether to invest in particular markets, and how to engage with national governments can have transformative effects on national economies and on the shape of the international economic order.

The relationship between multinational corporations and the international system is complex and multidimensional. MNCs are major actors in the global economy, driving the expansion of trade and investment, facilitating the transfer of technology and management practices, and creating complex networks of economic interdependence. But they are also political actors, engaging with national governments and international institutions to shape the regulatory environment within which they operate, lobbying for trade agreements and investment protections that serve their interests, and sometimes exercising significant influence over the foreign policies of their home states.

For developing states, the relationship with multinational corporations is particularly complex. MNCs can bring significant benefits — capital investment, employment creation, technology transfer, access to global markets, and tax revenues — but they can also create challenges, including the extraction of natural resources with limited local benefit, transfer pricing practices that reduce tax revenues, environmental degradation, and the creation of political dependencies that compromise state sovereignty. Managing the relationship with MNCs in ways that maximise the developmental benefits while minimising the costs is one of the central challenges of economic governance for developing states, including South Sudan, which has experienced the complex dynamics of oil company investment in particularly acute form.

6.5 Transnational Networks

Transnational networks are loose, often informal groupings of individuals and organisations that share information, coordinate activities, and advocate for common goals across national boundaries. The concept of the transnational advocacy network, developed by scholars Margaret Keck and Kathryn Sikkink, captures the way in which activists, researchers, lawyers, and other non-state actors can create powerful cross-border coalitions to promote normative change in international relations — putting pressure on both national governments and international institutions to adopt new standards on issues such as human rights, environmental protection, anti-corruption, and nuclear disarmament.

Transnational networks operate through what Keck and Sikkink call the 'boomerang effect': when domestic activists in a country are unable to influence their own government directly, they can appeal to transnational networks of activists and international organisations to put pressure on the government from outside, using international norms and institutions as leverage. This boomerang dynamic has been particularly important in the promotion of human rights norms: domestic human rights activists have repeatedly mobilised international attention to abuses by their own governments, using the framework of international human rights law and the advocacy of international NGOs to hold their governments accountable in ways that would not have been possible through purely domestic channels.

6.6 Global Civil Society

Global civil society refers to the totality of non-governmental, non-commercial organisations and networks that operate in the international sphere — a vast and diverse assemblage of associations, foundations, movements, faith-based organisations, professional associations, and other entities that constitute the international non-governmental sector. The growth of global civil society over the past several decades has been one of the most significant transformations of the international system, reflecting the deepening of globalisation, the communications revolution, and the growing recognition of the importance of non-state participation in the management of global challenges.

Global civil society organisations play multiple roles in the international system. They serve as advocates for human rights, environmental protection, and other normative goals, using their moral authority and access to information to influence the policies of states and international institutions. They provide humanitarian assistance in crisis situations — from refugee camps to post-conflict reconstruction — that states and international organisations alone cannot adequately address. They serve as monitors of state behaviour, documenting human rights abuses, electoral fraud, and other violations of international standards and bringing them to the attention of the international community. And they participate in the deliberative processes of international institutions — international conferences, treaty negotiations, and the work of UN agencies — providing expertise, representing the perspectives of affected populations, and helping to hold governments accountable.

Table 5: Actors in the International System — Types, Roles, Examples, and Relative Influence

7.0 Power and the International System

Power is the currency of international politics — the fundamental resource through which states advance their interests, protect their security, and shape the international environment to their advantage. The concept of power in international relations is complex and contested: it encompasses both material capabilities — military force, economic resources, technological capacity — and more diffuse forms of influence such as the ability to set international agendas, to shape other actors' preferences, and to attract rather than coerce. Understanding power — how it is distributed in the international system, how it is exercised, and how it relates to the structure and stability of the system — is essential to understanding the dynamics of international politics.

7.1 Distribution of Power among States

The distribution of power among states defines the basic hierarchy of the international system and shapes the structure within which all international actors must operate. Power is not distributed equally: some states command vastly greater military, economic, technological, and diplomatic resources than others, and this inequality has profound implications for the ability of different states to pursue their interests, to influence international outcomes, and to shape the rules and institutions of the international order. The recognition of this inequality is reflected in the institutional architecture of the post-1945 international order, most conspicuously in the permanent member status and veto power of the five great powers in the UN Security Council.

Contemporary assessments of the distribution of power in the international system suggest that we are in a period of significant flux. The clear American preponderance of the 1990s — the 'unipolar moment' — has given way to a more contested distribution, as China's rise has dramatically altered the economic balance of power and as other emerging powers — India, Brazil, Turkey, Indonesia, and others — have grown in both economic and political significance. Whether this shifting distribution will eventually crystallise into a stable new multipolarity, or whether it will produce a bipolar competition between the United States and China reminiscent of the Cold War, is one of the central questions of contemporary international relations.

For developing states and small states, the distribution of power in the international system creates a structural context of vulnerability. States with limited military and economic capabilities cannot realistically expect to deter the great powers through their own resources, to shape the rules of the international order through their individual efforts, or to resist the economic pressures that the major trading and financial powers can bring to bear. Their security depends on the credibility of international norms and institutions — the norm of state sovereignty, the prohibition on the use of force in international relations, the collective security mechanisms of the UN — that protect weaker states from the depredations of the powerful. The maintenance and strengthening of these normative and institutional protections is therefore a vital interest of small and developing states, including South Sudan.

7.2 Balance of Power Dynamics

The balance of power is one of the oldest and most enduring concepts in the theory and practice of international relations. In its simplest form, the balance of power refers to the tendency of states in a multipolar system to prevent any single state from achieving hegemony — from accumulating such a preponderance of power that it can dictate terms to all others — by forming balancing coalitions against any state that appears to be reaching for predominance. This tendency towards balance is held by realist theorists to be a structural consequence of the anarchic international system: states that value their survival and autonomy will always have an incentive to resist any actor that seeks to dominate the system, and will form coalitions to counter such attempts.

The historical record provides considerable support for the balance-of-power logic. The formation of grand coalitions to resist the hegemonic ambitions of France under Louis XIV and Napoleon, Germany under the Kaiser and Hitler, and the Soviet Union during the Cold War all illustrate the recurrence of balancing behaviour in international history. However, the record also reveals important limitations of the balance-of-power theory. States do not always balance against rising powers: sometimes they 'bandwagon' — align with the rising power rather than against it — when they perceive that balancing is costly, ineffective, or unnecessary. The theory also struggles to explain the timing and composition of balancing coalitions, the role of ideological factors in shaping alliance choices, and the conditions under which the balance of power fails to prevent hegemonic war.

In the contemporary international system, debates about balance-of-power dynamics focus particularly on how other states are responding to the rise of China and the relative decline of American preponderance. Some analysts see clear signs of balancing behaviour — the strengthening of US alliances in the Indo-Pacific, the development of security partnerships such as QUAD (the Quadrilateral Security Dialogue involving the US, Japan, Australia, and India), and the growing defence spending of states in China's neighbourhood. Others argue that the pattern is more mixed — that many states in the Asia-Pacific are hedging rather than explicitly balancing, seeking to maintain economic relationships with China while preserving security ties with the United States.

7.3 Hegemony in the International System

Hegemony refers to the condition in which one state — the hegemon — exercises a preponderant degree of power and influence in the international system, shaping the rules, institutions, and norms of international order in ways that reflect its interests and values. Hegemonic stability theory, associated with scholars such as Charles Kindleberger and Robert Gilpin, argues that a hegemonic state performs important systemic functions — providing public goods such as a stable international currency, open trading arrangements, and security guarantees — that are essential for the functioning of the international economy and the maintenance of international order.

The post-1945 international order has been closely associated with American hegemony. The United States used its preponderant power and international prestige after the Second World War to construct the institutional framework of the liberal international order — the United Nations system, the Bretton Woods institutions, the GATT, and the network of alliances and security guarantees that anchored the Western camp during the Cold War. This American-led order has provided significant benefits to its participants — an unprecedented expansion of trade and investment, a framework for managing international security challenges, and a set of norms and institutions that have constrained the behaviour even of powerful states. The question of whether this order can survive the relative decline of American power and the rise of new powers with different interests and values is one of the most pressing questions facing the international system in the twenty-first century.

7.4 Power Transitions and System Change

Power transitions — periods in which the relative power of major states shifts significantly, altering the hierarchy of the international system — are among the most dangerous and consequential dynamics in international politics. Power transition theory, as developed by Organski and his collaborators, identifies the period of rough parity between a rising challenger and the established dominant power as the most dangerous moment in the transition process: when the challenger has grown sufficiently powerful to contest the existing order but has not yet achieved clear dominance, the temptation for either side to use force to resolve the contest before the balance tips further may be at its highest.

The historical record of power transitions is sobering. The transition from British to American hegemony in the late nineteenth and early twentieth centuries was managed relatively peacefully — partly because of the close cultural and institutional ties between the two Anglo-Saxon powers and partly because the United States ultimately shared Britain's commitment to an open, rule-based international order. The German challenge to British hegemony in the same period, by contrast, ended in two world wars. The rise of China as a potential challenger to American hegemony is therefore being watched with intense concern by scholars and policymakers, with the 'Thucydides trap' — the concept, drawn from the Athenian historian's account of the Peloponnesian War, that the rise of a new power almost inevitably brings it into conflict with the established dominant power — providing a widely cited if contested framework for thinking about the risk of Sino-American conflict.

7.5 Global Power Rivalries

The contemporary international system is characterised by a complex pattern of global and regional power rivalries that shape the security environment, constrain the policy choices of smaller states, and generate the most significant risks of large-scale conflict. The defining rivalry of the current era is that between the United States and China, which plays out across multiple domains: military competition in the Indo-Pacific; economic competition over trade, technology, and global supply chains; diplomatic competition for influence in international institutions and in developing regions including Africa and Latin America; and ideological competition between democratic capitalism and the authoritarian state capitalism model that China represents.

The Russia-Ukraine war that began with Russia's full-scale invasion in February 2022 has added a second major great-power rivalry — between Russia and the Western alliance — to the strategic landscape. The war has had profound implications for the international system: it has reinvigorated NATO and sharpened the cleavage between the democratic West and the authoritarian powers; it has demonstrated the continued relevance of conventional military force in great-power competition; and it has raised fundamental questions about the sustainability of the post-Cold War European security order and the future of the rules-based international order more broadly.

Table 6: Major Global Power Structures — Historical Examples, Dominant Powers, and Key Dynamics

8.0 Contemporary Changes in the International System

The international system of the early twenty-first century is undergoing a period of rapid and far-reaching transformation, driven by a confluence of structural shifts, technological changes, and new transnational challenges that are collectively reshaping the architecture of global politics. The comfortable certainties of the post-Cold War unipolar moment — the triumphalism about liberal democracy and market capitalism, the optimism about the deepening of international cooperation, and the confidence in the stability of the American-led international order — have given way to a more uncertain and contested era in which the fundamental norms, structures, and institutions of the international system are subject to challenge and contestation from multiple directions. This section examines five major dimensions of contemporary change in the international system.

8.1 Globalization and Interdependence

Globalisation — the accelerating integration of national economies, societies, and polities through the cross-border movement of goods, capital, people, and ideas — has been one of the most powerful drivers of change in the international system over the past half-century. The globalisation of the world economy has created unprecedented levels of economic interdependence among states, integrated hundreds of millions of people into global production chains and markets, generated remarkable improvements in living standards in many parts of the developing world (most spectacularly in China, India, and East Asia), and created new forms of transnational civil society and political identity that cut across national boundaries.

At the same time, globalisation has generated significant discontents. The distributional consequences of economic integration have been uneven, with some regions and populations benefiting greatly while others have experienced stagnating wages, deindustrialisation, and growing inequality. The financial crisis of 2008 exposed fundamental vulnerabilities in the globally integrated financial system and demonstrated that financial contagion can spread rapidly across borders with devastating consequences for national economies. The COVID-19 pandemic demonstrated the vulnerability of globally integrated supply chains to disruption and raised new questions about the risks of excessive dependence on distant suppliers for essential goods. And the rise of economic nationalism — manifested in trade protectionism, investment restrictions, and the partial decoupling of national economies — has challenged the liberal economic order on which the globalisation project was premised.

The relationship between globalisation and the power of the state is one of the most debated questions in contemporary international relations. Hyperglobalists argue that the power of the state is being fundamentally eroded by global markets, transnational corporations, and supranational institutions, while sceptics argue that states remain the primary actors in managing globalisation and that the degree of economic integration is often overstated. A middle position — the 'transformationalist' perspective — argues that globalisation is transforming but not eliminating the power of the state, forcing governments to adapt their roles and capacities to the new demands of managing an integrated global economy while maintaining political accountability to national populations.

8.2 Rise of Emerging Powers

One of the most significant structural changes in the contemporary international system is the rise of a group of large, economically dynamic states — the so-called 'emerging powers' or 'rising powers' — whose growing economic and political capabilities are challenging the dominance of the established Western powers that have shaped the international system since the Second World War. China is by far the most important and consequential of these rising powers, having experienced several decades of sustained economic growth that has made it the world's second-largest economy (or largest by some measures of purchasing power parity), the world's largest exporter, and a growing military power with ambitions to reshape the rules and institutions of the international order in ways more favourable to its interests.

Beyond China, a range of other emerging powers — including India, Brazil, South Africa, Turkey, Indonesia, and Mexico — have grown in economic significance and are increasingly asserting their interests and identities in international forums. The BRICS grouping (Brazil, Russia, India, China, South Africa) and its recent expansion to include additional members represents one institutional expression of the growing ambition of emerging powers to reshape the international order. The G20, which emerged from the financial crisis of 2008 as the premier forum for international economic governance, reflects the growing recognition that an international economic order managed exclusively by the G7 Western powers is no longer adequate.

For Africa and South Sudan, the rise of China is particularly significant. China has become the largest bilateral trading partner and the largest source of infrastructure investment for many African states, reshaping the economic landscape of the continent and offering an alternative source of development finance to the traditional Western donors and multilateral institutions. The Chinese model of development cooperation — which typically involves infrastructure lending, resource extraction, and limited conditions on governance — has been welcomed by some African leaders as a more respectful and non-prescriptive alternative to Western development assistance, while critics have raised concerns about the sustainability of Chinese loans, the employment practices of Chinese companies, and the political leverage that large debt obligations give China over borrowing governments.

8.3 Expansion of International Institutions

Despite the strains and contestation that the contemporary international system is experiencing, the post-war trend towards the proliferation and deepening of international institutions has continued. The number of international organisations, treaty regimes, and multilateral agreements has continued to grow, extending the institutional framework of international governance into new areas — including cyber governance, climate change, global health, and financial regulation — and deepening its reach in established areas such as trade, investment, and human rights. The development of international criminal justice — the creation of the International Criminal Court in 2002 and the prosecution of individuals for war crimes, crimes against humanity, and genocide — represents a particularly significant development, establishing for the first time a permanent international institution with the mandate and capacity to hold individuals accountable for the most serious violations of international humanitarian law.

At the same time, international institutions are under significant strain. The United Nations Security Council has been increasingly paralysed by great power tensions, with the use or threat of the Russian and Chinese vetoes blocking effective international responses to conflicts in Syria, Ukraine, and other contexts. The World Trade Organisation's dispute settlement system has been weakened by the United States' blocking of new appointments to the Appellate Body. The Paris Agreement on climate change represents a significant institutional achievement, but the adequacy of national commitments and the mechanism for accountability remain major concerns. And the International Criminal Court faces challenges to its legitimacy and jurisdiction, including from major powers that have not ratified the Rome Statute and from African states that have expressed concern about the perceived selectivity of its prosecutions.

8.4 Technological Transformation

Technological change — the development and deployment of new technologies in ways that alter the capabilities, strategies, and vulnerabilities of international actors — has always been a driver of change in the international system. But the pace and scope of technological change in the contemporary era are unprecedented, and the implications for the international system are profound. The digital revolution — the development of the internet, artificial intelligence, big data, robotics, and other information and communication technologies — is transforming every aspect of international relations, from military strategy and intelligence to economic competition, diplomatic communication, and the dynamics of domestic political stability.

In the military domain, the development of cyber warfare capabilities has created a new domain of strategic competition in which state and non-state actors can conduct offensive operations against adversaries' critical infrastructure, military systems, and political processes with a degree of anonymity and deniability that conventional military operations do not permit. The widespread use of social media by state and non-state actors to conduct information warfare — spreading disinformation, manipulating public opinion, and undermining the democratic processes of adversary states — represents a novel form of political competition that is difficult to counter and that is challenging the resilience of democratic institutions. And the development of autonomous weapons systems — lethal drones and robots capable of selecting and engaging targets without direct human control — raises profound ethical and strategic questions about the future of warfare.

8.5 New Security Challenges

The contemporary international system faces a set of security challenges that differ fundamentally in character from the traditional inter-state security challenges that dominated Cold War strategic thinking. These new security challenges are typically transnational in origin and impact, requiring cooperative international responses rather than unilateral state action; they are often driven by non-state actors or by state failure rather than by the deliberate aggression of sovereign states; and they frequently interact with and amplify one another in complex ways that are difficult for traditional security frameworks to manage.

Transnational terrorism — most dramatically illustrated by the September 11, 2001 attacks and their aftermath — has emerged as one of the defining security challenges of the contemporary era. Terrorist networks that operate across state boundaries, exploiting ungoverned spaces, global communications technologies, and the vulnerabilities of open societies, pose challenges that conventional military responses are poorly suited to address. The 'war on terror' launched by the United States after September 11 demonstrated both the scale of the security threat and the limitations and costs — human, financial, and political — of attempting to manage it primarily through military means.

Climate change is increasingly recognised as a security challenge of the first order — a threat multiplier that exacerbates existing vulnerabilities, drives resource conflicts, undermines food and water security, and displaces populations in ways that can generate political instability and conflict. For Africa, which is among the most vulnerable regions to the impacts of climate change despite having contributed the least to the stock of greenhouse gases that drive it, the security implications of climate change are particularly acute. South Sudan — already one of the world's most fragile states — faces the compounding threat of climate-driven disruptions to agricultural production, pastoralism, and water resources that could exacerbate the communal conflicts and economic vulnerabilities that have characterised its troubled recent history.

9.0 Challenges Facing the International System

The contemporary international system faces a formidable array of challenges that test the resilience of its institutions, norms, and cooperative frameworks. These challenges reflect both the enduring tensions of anarchic international politics — competition for power, the management of conflict, the protection of sovereignty — and the new transnational challenges of the twenty-first century that require cooperative responses from a system that is better designed for managing competition than for delivering collective goods. This section examines five of the most significant challenge areas facing the international system.

9.1 Global Power Competition

The intensification of great-power competition is perhaps the most fundamental challenge facing the contemporary international system. The rise of China as a peer competitor to the United States, the resurgence of Russian assertiveness, and the growing ambitions of other regional powers have created a more competitive and contested international environment in which the rules, institutions, and norms that constitute the liberal international order are under sustained challenge. Great-power competition is being played out across multiple domains — military, economic, technological, ideological — and is generating pressures for decoupling and fragmentation that challenge the integrated global systems that have characterised the post-Cold War era.

The particular danger of the current great-power competition lies in the potential for miscalculation and unintended escalation in a system that lacks the stable deterrence framework and established communication channels of the Cold War. The Cold War competition, for all its risks, was structured by a degree of mutual understanding between the superpowers — about red lines, about the mechanisms of crisis management, and about the shared interest in avoiding nuclear war — that the contemporary Sino-American competition has not yet fully developed. The absence of robust crisis management mechanisms between the United States and China, the ideological hostility between the two systems, and the domestic political pressures on both governments all increase the risk of a crisis spiralling into conflict.

For smaller and developing states, the intensification of great-power competition creates difficult choices between alignment and neutrality, between the economic benefits of engagement with China and the security benefits of alignment with the United States, and between the norms of the liberal international order and the alternative frameworks that revisionist powers are promoting. The experience of African states — courted simultaneously by the United States, China, Russia, and other powers — illustrates the complex navigation that small states must perform in a competitive multipolar environment.

9.2 International Conflicts and Wars

Armed conflict — both inter-state war and intra-state conflict — remains one of the most destructive and persistent challenges facing the international system. Despite the decline in the frequency of inter-state war that characterised the post-Cold War period — a decline attributed by various scholars to the spread of democracy, the increasing economic costs of war, the strength of international norms against aggression, and the deterrent effect of nuclear weapons — the early twenty-first century has seen the return of large-scale inter-state conflict with Russia's invasion of Ukraine and the ongoing conflicts in the Middle East. Intra-state conflict — civil wars, insurgencies, and communal violence — has remained endemic in many regions, particularly in sub-Saharan Africa and the Middle East, causing enormous humanitarian suffering and generating massive displacement.

The international system's mechanisms for managing armed conflict have been under severe strain. The UN Security Council's collective security function — designed to respond to threats to international peace and security with coordinated international action — has been increasingly paralysed by great-power disagreements, with Russia's veto blocking effective Council responses to Russian aggression in Ukraine and with China's growing willingness to use or threaten its veto limiting the Council's responses to other conflicts. Regional organisations such as the African Union have sought to fill some of the gap, but they lack the resources and enforcement capabilities needed to manage major conflicts effectively.

9.3 Economic Inequality

Economic inequality — both within and among states — is one of the most profound and destabilising challenges facing the international system. The gap between the richest and poorest states in the international system remains enormous: the per capita income of the wealthiest states is hundreds of times that of the poorest, and the differences in access to healthcare, education, infrastructure, and economic opportunity are correspondingly vast. This inequality is not simply a moral challenge: it generates political instability, drives migration and displacement, and undermines the legitimacy of the international order in the eyes of populations that experience its benefits and burdens very unequally.

The international economic system has been criticised by scholars and activists from the developing world as structurally biased in favour of the rich developed states, which have used their dominant position in international institutions — particularly the IMF, the World Bank, and the WTO — to shape the rules of the international economy in ways that serve their interests at the expense of developing states. The conditionality attached to IMF and World Bank lending — which typically requires recipient states to adopt market-oriented economic policies regardless of their developmental appropriateness — has been a particular source of controversy, as has the asymmetric access to global markets that developing countries face as a result of agricultural subsidies and other protectionist policies in the developed world.

For South Sudan, economic inequality is both an internal challenge — the country's oil wealth has been very unequally distributed, with the conflict over resource revenues being a major driver of the civil war — and an international challenge — the limited economic capabilities of the country make it heavily dependent on external aid and investment and vulnerable to the economic conditionality that comes with that dependence. Building a more equitable domestic economic order while navigating the asymmetries of the international economic system is one of the central challenges of South Sudan's post-conflict development agenda.

9.4 Environmental and Climate Challenges

Environmental degradation and climate change represent existential challenges to the international system in a way that distinguishes them from most other challenges the system faces. The scientific consensus on the reality and severity of anthropogenic climate change is overwhelming: the continued emission of greenhouse gases at current rates will produce a level of global warming that threatens to disrupt agricultural systems, raise sea levels, intensify extreme weather events, and create conditions of heat and drought that will render significant parts of the inhabited world uninhabitable for human populations within the timeframe of current policy planning. Managing this challenge requires a degree of global cooperation — reducing greenhouse gas emissions across all major emitting countries — that the international system, organised around the competing national interests of sovereign states, has so far struggled to deliver.

The international climate regime — centred on the UN Framework Convention on Climate Change (UNFCCC) and the Paris Agreement adopted under it in 2015 — represents a significant institutional achievement, establishing a framework for national commitments to emissions reduction and a mechanism for international accountability. However, the gap between the commitments made under the Paris Agreement and the reductions needed to limit global warming to the internationally agreed target of 1.5 degrees Celsius is enormous, and the failure of major emitters — particularly the United States (which withdrew from the Paris Agreement under the Trump administration before rejoining under Biden) and China (the world's largest current emitter) — to make commitments commensurate with the scale of the challenge remains a critical weakness of the international climate response.

9.5 Transnational Security Threats

Transnational security threats — threats that originate from or operate across national borders and that require cooperative international responses — represent one of the defining security challenges of the contemporary era. These threats include transnational terrorism, organised crime and drug trafficking, cybercrime and cyber warfare, pandemic disease, nuclear proliferation, and the illicit trade in conventional weapons. Each of these threats is characterised by its cross-border character, its exploitation of the openness and interdependence of the globalised international system, and its resistance to management by individual states acting alone.

The governance of transnational security threats is complicated by the asymmetry between the threats themselves — which are inherently international — and the mechanisms of governance — which remain primarily national. States are understandably reluctant to delegate significant authority over security to international institutions, reflecting deep-seated concerns about sovereignty and the risk of becoming dependent on the decisions of international bodies over which they have limited control. Yet the management of transnational threats requires precisely the kind of information sharing, joint operations, and coordinated policy-making that effective international governance would provide. Bridging this gap between the international character of the threats and the national character of governance remains one of the fundamental institutional challenges of the contemporary international system.

10.0 Future of the International System

The future of the international system is, by its nature, uncertain — shaped by structural trends that can be identified and analysed but also by the contingent choices of states and other actors, the unpredictable effects of technological change, and the possible emergence of new challenges and crises that lie beyond the horizon of current foresight. Nevertheless, several major structural trends can be identified that are likely to shape the evolution of the international system over the coming decades, and a serious effort to understand and anticipate these trends is an essential element of both scholarly analysis and practical foreign policy-making. This section examines five key dimensions of the future international system.

10.1 Emerging Multipolar World

The most fundamental structural trend in the contemporary international system is the transition from the American-dominated unipolarity of the post-Cold War period to a more complex multipolar order. This transition is being driven by the economic and political rise of China — which has emerged as a peer competitor to the United States in economic terms and is rapidly closing the gap in military capabilities — and by the growing significance of a range of regional powers whose growing capabilities and assertiveness are reshaping the balance of influence in their respective regions. The contours of the emerging multipolar order are still taking shape, and there is considerable debate among scholars about whether it will involve a relatively stable concert of major powers, a dangerous bipolar competition between the United States and China, or a more fragmented regional order in which different great powers exercise spheres of influence in their respective neighbourhoods.

The implications of multipolarity for international stability and governance are mixed. On the positive side, a more multipolar world may provide more diverse sources of leadership and norm-setting, reducing the concentration of power in a single hegemon and creating more opportunities for smaller states to pursue their interests by balancing among competing powers. On the negative side, multipolarity creates more complex strategic calculations, increases the risk of miscalculation and misperception, and makes it harder to coordinate on the provision of international public goods such as climate protection, global health security, and financial stability. The historical record of multipolar systems — which includes the catastrophic systemic breakdown of the First World War — provides some grounds for concern about the stability of the emerging order.

10.2 Role of International Institutions

International institutions will remain central to the management of global politics in the future international system, but their character, composition, and effectiveness are likely to change significantly. The existing institutional framework of the international system — built primarily by and for the Western powers in the aftermath of the Second World War — is under pressure from multiple directions: from rising powers that seek greater voice and representation in international institutions; from populist and nationalist movements in established democracies that challenge the legitimacy of international commitments; and from the sheer scale and complexity of the new challenges — climate change, pandemic disease, cyber security, artificial intelligence governance — that require institutional responses for which the existing framework was not designed.

The reform and adaptation of international institutions to the realities of the twenty-first century is therefore one of the most urgent tasks facing the international community. Some of the most important reforms needed are structural: giving the major emerging powers — China, India, Brazil, and others — greater representation and voice in the governance of the international financial institutions and the UN Security Council. Others are functional: developing new institutional frameworks for the governance of climate change, digital technologies, and other areas where existing institutions are inadequate. And others are normative: developing shared understandings and principles for the governance of new domains that are currently contested — such as the governance of artificial intelligence, the management of outer space, and the regulation of autonomous weapons.

10.3 Global Governance and Cooperation

Global governance — the management of global challenges through a combination of multilateral institutions, international law, transnational networks, and the voluntary coordination of national policies — will become increasingly important in the future international system, as the density and severity of global challenges that require cooperative responses continues to grow. The concept of global governance does not imply world government: it refers to the diverse array of governance mechanisms and actors — from formal international organisations to informal norms and practices — that together provide a degree of management and coordination in the absence of a central global authority.

The prospects for effective global governance in the future international system are uncertain. The combination of great-power competition, rising nationalism, institutional strain, and the increasing complexity of global challenges creates formidable obstacles to the kind of cooperative governance that many of these challenges require. Yet the interdependence of states and the global character of many of the most pressing threats — climate change, pandemic disease, financial instability, cyber threats — also create powerful incentives for cooperation that are likely to sustain at least some degree of multilateral engagement even in a more competitive international environment. The challenge for practitioners and policymakers is to identify the forms and areas of cooperation where international coordination is most valuable and most feasible, and to design institutions and processes that can deliver that cooperation despite the pressures of competitive geopolitics.

10.4 Technological Influence on Global Politics

Technological change will continue to be one of the most powerful drivers of transformation in the international system over the coming decades. Artificial intelligence — the development of machine systems capable of performing tasks that previously required human intelligence — is likely to have particularly profound implications for international relations, affecting everything from military strategy and intelligence analysis to economic productivity and the dynamics of domestic political stability. The competition between the United States and China over AI capabilities has already emerged as one of the central fronts of great-power technological competition, with both governments making massive investments in AI research and development and imposing restrictions on the transfer of AI-related technologies to the other side.

The governance of new technologies in the international system raises profound challenges. Emerging technologies typically develop faster than the international institutions and norms needed to govern them, creating windows of regulatory vacuum in which powerful actors can exploit their advantages without international constraint. The development of autonomous weapons systems, for example, has outpaced international efforts to regulate their use, and the absence of agreed international norms on the use of lethal autonomous weapons raises serious concerns about the future of the laws of war. Similarly, the rapid development and deployment of AI systems in high-stakes domains — financial markets, criminal justice, military targeting — is outpacing the development of governance frameworks that can ensure their responsible use.

10.5 Prospects for International Stability

The prospects for international stability in the coming decades are deeply uncertain, reflecting the interaction of structural trends that pull in different directions. The transition to multipolarity, the intensification of great-power competition, the stress on international institutions, the proliferation of transnational security threats, and the growing urgency of global challenges such as climate change all generate pressures on the stability of the international system. At the same time, the enormous costs of major war in a nuclear-armed world, the deep economic interdependence among the major powers, the extensive framework of international institutions and law, and the growing capabilities of global civil society and transnational advocacy networks all create powerful incentives for the management of competition within non-violent bounds.

For small and developing states — including South Sudan — the key question is not simply whether the international system will remain stable but whether it will evolve in ways that are more or less hospitable to their interests and aspirations. A world in which great-power competition crowds out international cooperation on development and climate change, in which the rules of the international order are reshaped to serve the interests of rising powers rather than the global community, and in which international institutions are weakened rather than reformed would be a more challenging environment for small and developing states than the imperfect but relatively supportive international order of recent decades. Advocating for a reformed and strengthened multilateral order — one that gives greater voice to developing states and that prioritises global public goods over great-power interests — is therefore a strategic priority for countries like South Sudan and their regional partners in the African Union.

11.0 Conclusion

This module has provided a comprehensive examination of the international system — the foundational concept through which international relations as a discipline makes sense of the complex, contested, and consequential world of global politics. Beginning with the conceptual and definitional foundations of the concept, tracing its historical evolution across several centuries of systemic transformation, analysing its structural characteristics and the actors who populate it, and examining both the dynamics of power that animate it and the contemporary challenges and future trends that are reshaping it, the module has sought to give students the analytical tools needed to understand how the international system works, why it has the characteristics it does, and where it appears to be heading.

11.1 Summary of the International System

The international system, as we have seen, is defined by several foundational characteristics: its anarchic ordering principle, which means the absence of any supreme authority above the level of the sovereign state; the formal sovereign equality of its member states, which coexists with deep inequalities of actual power and influence; the role of power distribution in shaping systemic structure, with different configurations of unipolarity, bipolarity, and multipolarity associated with different patterns of behaviour and stability; the growing significance of non-state actors alongside the continued centrality of states; and the extensive framework of international norms, institutions, and law that has developed to manage the competitive dynamics of anarchy.

The history of the international system illustrates both the durability of its foundational Westphalian architecture — sovereign statehood, non-interference, formal legal equality — and the capacity of the system to undergo fundamental structural transformations in response to shifts in the distribution of power, ideological changes, and the emergence of new challenges. The transition from the bipolar Cold War system to the post-Cold War unipolar order, and the current transition from unipolarity to an emerging multipolarity, are the most recent and consequential of these systemic transformations, and their management will be the defining challenge of international statecraft in the coming decades.

11.2 Importance of Understanding Systemic Dynamics

Understanding the dynamics of the international system is essential for any serious student of international relations, foreign policy, or global governance. The decisions made by states in the international arena — on questions of alliance, security, economic policy, and institutional engagement — are shaped in fundamental ways by the structural characteristics of the international system in which they are made. A state that understands the systemic context within which it operates — the distribution of power, the incentives and constraints of anarchy, the opportunities and limitations of international institutions, and the dynamics of great-power competition — is better positioned to make informed and effective foreign policy choices than one that acts without this systemic awareness.

For students who will go on to careers in diplomacy, international organisations, development, or other fields of international work, the analytical frameworks introduced in this module — structural realism, liberal institutionalism, English School, constructivism — provide essential conceptual tools for making sense of the complex and rapidly changing international environment. No single theoretical framework captures the full complexity of the international system, and the ability to draw on multiple theoretical perspectives — to recognise when the logic of realist power politics is operating, when institutional frameworks are providing effective management, and when ideational factors and normative change are reshaping the system — is the mark of sophisticated international analysis.

11.3 Future Directions of the Global Political Order

The future direction of the global political order is uncertain, but several structural trends can be identified with reasonable confidence. The transition from unipolarity to multipolarity is likely to continue, driven by China's sustained economic and military growth and the growing assertiveness of regional powers. The stress on existing international institutions is likely to intensify, creating both pressures for reform and risks of institutional breakdown. The range and severity of transnational challenges requiring collective international responses — climate change, pandemic preparedness, cyber security, artificial intelligence governance — will grow, increasing the demand for effective global governance even as great-power competition makes its supply more difficult.

For South Sudan and other developing states in Africa and the Global South, the future international system offers both opportunities and challenges. The rise of China and other emerging powers creates new sources of investment and development finance, new trading partners, and new diplomatic alignments that can expand the strategic options available to African states. The growing significance of non-state actors and global civil society creates new platforms for advocacy and accountability that can support African states' interests in international forums. And the increasing urgency of global challenges such as climate change creates new opportunities for African states to exercise leadership and influence, as the continent that is most vulnerable to the impacts of climate change and that stands to gain most from an ambitious international response.

At the same time, the intensification of great-power competition risks diverting international attention and resources from development and global challenges to great-power rivalry. The weakening of international institutions and the erosion of the rules-based international order removes important protections for smaller states. And the governance deficits in the management of new technologies and new transnational challenges create risks and vulnerabilities that are likely to fall disproportionately on the most vulnerable states and populations. Navigating this complex and uncertain future international system will require both analytical sophistication and diplomatic skill — precisely the capabilities that this course is designed to develop.

Suggested Discussion Questions

1. What is the international system in international relations? Drawing on the scholarly definitions examined in this module, explain the key dimensions of the concept and discuss why it is considered foundational to the study of international relations.
2. Explain the different structural configurations of the international system — unipolarity, bipolarity, and multipolarity — and analyse their respective implications for international stability and state behaviour. In your answer, draw on relevant historical examples.
3. How does the distribution of power influence the international system? In your answer, discuss balance-of-power dynamics, hegemonic stability theory, and power transition theory, and consider the implications of the current power transition for the stability of the international order.
4. Discuss the major changes in the international system after the Cold War. What structural transformations has the system undergone since 1991, and what are the most significant challenges and opportunities these changes present for developing states in Africa?
5. To what extent has anarchy in the international system been 'tamed' by the development of international institutions, international law, and shared norms? Drawing on the perspectives of both structural realists and liberal institutionalists, evaluate the capacity of the international system to manage its inherent competitive dynamics through cooperative means.

Suggested Case Studies

Case Study 1: South Sudan and the Anarchic International System

South Sudan's experience since independence in 2011 provides a compelling and locally relevant case study of how the anarchic international system shapes the security environment and foreign policy choices of a newly independent developing state. The outbreak of civil war in December 2013, the involvement of neighbouring states and regional powers in the conflict, the response of the international community through the UN Mission in South Sudan (UNMISS) and the IGAD-led peace process, and the continuing challenges of post-conflict reconstruction all illustrate key dynamics of the international system examined in this module: the security dilemma, the role of regional institutions, the politics of humanitarian intervention, and the interaction between the international system and domestic political order.

Case Study 2: The Cold War as a Bipolar International System

The Cold War (1947–1991) provides the canonical modern example of a bipolar international system and offers rich material for examining the theoretical claims of structural realism about the dynamics and stability properties of different systemic configurations. The competition between the United States and the Soviet Union — in military capabilities, ideological influence, economic models, and geopolitical alignment — shaped the behaviour of virtually every state in the international system, including the newly independent states of Africa that were drawn into the superpower competition through the proxy conflicts of the Cold War era. Examining the Cold War through the lens of structural theory illuminates both the strengths and the limitations of structural approaches to international relations.

Case Study 3: China's Rise and the Challenge to the Liberal International Order

The rise of China is the most consequential structural transformation in the contemporary international system, raising fundamental questions about the durability of the American-led liberal international order and the direction of systemic change. China's economic growth, its expanding military capabilities, its assertiveness in territorial disputes in the South and East China Seas, its development of alternative international institutions and frameworks, and its challenge to Western norms on democracy, human rights, and internet governance all illustrate key dynamics examined in this module: power transition theory, the contestation of hegemony, the relationship between rising powers and international institutions, and the ideational dimensions of systemic competition. Examining China's rise through the analytical frameworks of this module provides a valuable exercise in applying international relations theory to the most significant contemporary challenge facing the international system.

Case Study 4: Climate Change and the Limits of International Cooperation

The international response to climate change provides a revealing case study of both the possibilities and the limitations of international cooperation in an anarchic international system. Despite overwhelming scientific consensus on the reality and severity of anthropogenic climate change, and despite decades of international negotiations under the UNFCCC, the international community has so far failed to deliver emissions reductions commensurate with the scale of the threat. Examining why this has been the case — through the lens of the collective action problem, the free-rider problem, the politics of global distributional equity, and the dynamics of great-power competition — illuminates fundamental features of the international system's capacity (and incapacity) for cooperative governance in the face of global challenges. For African states including South Sudan, the climate governance case is also a powerful illustration of the inequities of the international system, in which the most vulnerable populations bear the costs of a problem created primarily by the most powerful.