Public financial management (PFM) reforms in post-conflict settings often appear technically sound yet fail to achieve durable change when budget systems are embedded in coalition maintenance and coercive resource allocation. Focusing on South Sudan, with comparative reference to Liberia and Sierra Leone, this study examines how “capability-trapped” budget reforms shape political order from the mid-2000s to the present. The analysis brings together PFM theory, the political economy of budgeting, and “good enough governance” perspectives. It is grounded in a research design that combines budget execution analysis, close reading of PEFA assessments and audit reports, interviews with reform participants, and cross-case comparison of fragile-state PFM trajectories. The central argument is that persistent reform failure is not best understood as a series of discrete policy breakdowns or temporary crises. Instead, it reflects the reproduction of linked institutional and political mechanisms that continuously reshape incentives, authority, and access to public resources. These mechanisms embed budgeting within systems of political survival, limiting the transformative potential of formal reforms. The study traces how these dynamics operate in practice, the variation they produce across cases, and why reform agendas that overlook the underlying political settlement tend to yield only partial or short-lived gains. By integrating conceptual insights with comparative evidence, the article offers both a theoretical synthesis and an empirically grounded interpretation of the South Sudan case. Its broader implication is that durable PFM reform requires more than technical fixes: it depends on institutional redesign, political bargaining, and accountability strategies capable of engag