Between Escalation and Erosion: Risk Hierarchies and Three Southeast Asian Claimants in the South China Sea

Why do the Philippines, Vietnam and Malaysia vary in their responses to comparable Chinese grey-zone coercion in the South China Sea? This article develops an episode-level risk-hierarchy explanation covering 2009–2025. Governments first screen prospective losses for likelihood and severity; among salient risks, they prioritise those that are most immediate and least controllable. Single-dominant, co-dominant and cumulative hierarchies generate different portfolios of legal referral, diplomatic diffusion, bounded deterrence, risk acceptance, risk absorption, and leverage expansion. Process tracing based on public evidence shows that the three states combine resistance and restraint differently as risk rankings shift across episodes. The Philippines’ legal referral and transparency, Vietnam's managed operational flexibility, and Malaysia's low-visibility controlled firmness therefore represent internally consistent strategies. They are portfolios designed to prevent positional erosion while keeping escalatory rupture politically manageable. The findings clarify how smaller states exercise agency under persistent sub-war coercion and why comparable pressure generates divergent policy choices.