China deploys maritime silk road infrastructure and economic leverage to pursue South China Sea territorial ambitions in Southeast Asia

China’s 21st Century Maritime Silk Road (MSR) in Southeast Asia represents a sophisticated geopolitical instrument that extends well beyond its proclaimed economic development objectives. Drawing on qualitative case study methodology across Myanmar, Cambodia, Malaysia, and the Philippines, this study investigates how Beijing systematically deploys MSR infrastructure investments to advance its South China Sea territorial ambitions. Analysis reveals three interlocking mechanisms: the development of dual-use port facilities at strategically critical locations; the cultivation of asymmetric economic dependencies that progressively constrain recipient states’ policy autonomy; and the deliberate fragmentation of ASEAN cohesion through calculated “bilateralization” strategies. Case evidence demonstrates compelling correlations between BRI investment flows and consequential foreign policy shifts—most starkly in Cambodia’s systematic obstruction of collective ASEAN positions and the Philippines’ dramatic pivot under Duterte from legal confrontation to strategic accommodation.