Gray-Zone Maritime Rights-Protection Strategy: Asymmetric Costs and Sustainable Presence, A Case Study of the China–Philippines Dispute over Scarborough Shoal

This working paper develops a Cost–Distance–Frequency (CDF) analytical framework to examine sustained maritime rights-protection operations under gray-zone conditions characterized by geographic asymmetry. Moving beyond episodic tactical encounters, the framework models cost per effective hour of presence by integrating transit distance, sortie frequency, platform mix, risk expectation, and policy-defined sustainability thresholds. Applying the CDF framework to the China–Philippines dispute over Scarborough Shoal, the paper demonstrates how near-shore advantages rooted in proximity and high-frequency deployment can be structurally offset over time through far-shore cost compression, prepositioned logistics, and manned–unmanned force integration. The analysis highlights the dynamic interaction between operational tempo, cumulative cost, and incident risk in shaping long-term strategic symmetry. Rather than prescribing policy choices, the study offers a generalizable analytical tool for evaluating the sustainability of maritime presence in contested environments. The framework is intended to support comparative scenario analysis, force-posture design, and endurance-based assessment of gray-zone competition.The framework is designed for comparative and structural analysis rather than precise empirical forecasting.