This article examines the economic and governance effects of UNMISS as an employer, buyer, infrastructure actor, and practical competitor to state institutions in UNMISS in South Sudan with comparative references to MONUSCO and AMISOM/ATMIS. It asks how peacekeeping-mediated political economy structures political order during from state independence through the civil war years to recent mission restructuring, combining critical peacekeeping studies, local political economy of peace operations, and humanitarian economy analysis with a research design centred on budget and procurement analysis, labour-market inquiry, interviews with mission personnel and local stakeholders, and comparison with other large African peace operations. The central argument is that the issue under study is not best explained as a discrete policy failure or a short-lived crisis. Rather, it is reproduced through linked institutional and political mechanisms that reshape incentives, authority, and access to resources over time (Pouligny, 2006; Whitworth, 2004) (Higate & Henry, 2009; Jennings, 2015). Across the paper, the analysis tracks how these mechanisms operate in practice, what variation they generate, and why reform agendas that ignore the underlying political settlement rarely succeed. The article therefore contributes both a conceptual synthesis and a grounded comparative interpretation of the focal case. Its wider implication is that durable reform requires institutional redesign, political bargaining, and accountability strategies capable of reaching the real sites where power is exercised (Carbonnier, 2014; Bellamy & Williams, 2013) (UNMISS, 2024; Cuddington & Langford, 2017).