A Review of the U.S. Positions Favorable to Japan in Northeast Asia Island Disputes ：Based on Gilpin’s Theory of Hegemonic Stability

Abstract

This paper investigates a significant transformation in U.S. foreign policy: the shift from long-standing strategic ambiguity to a clearer and more explicit partiality toward Japan in managing island disputes in Northeast Asia. Specifically, it addresses the research question: Why has the United States adjusted its stance to increasingly support Japan’s territorial claims over the Diaoyu/Senkaku Islands, the Southern Kurils, and Dokdo/Takeshima? To answer this, the study adopts Robert Gilpin’s theory of hegemonic stability and hegemonic decline as its analytical framework, arguing that the U.S. adjustment reflects a structural response to hegemonic retrenchment in the face of rising counterbalancing powers—namely China and Russia—and growing alliance frictions with South Korea. The research objectives are twofold: first, to identify and map the evolution of U.S. policy from neutrality to partiality across three key island disputes; second, to explain this shift within the broader context of declining hegemonic capacity and regional power realignment. The paper argues that the clearer U.S. position is not merely rhetorical, but a strategic recalibration designed to consolidate its alliance with Japan and sustain its regional dominance amid mounting geopolitical constraints. This study contributes to existing literature by linking U.S. policy change to systemic power transitions, rather than bilateral diplomacy or legal ambiguity alone. It also offers a unified analysis of three distinct disputes that are typically treated separately, providing a more comprehensive understanding of the logic behind U.S. strategic alignment in Northeast Asia.