ROK–U.S.–Japan “Operational” Security Cooperation for Responding to a Two-Front Crisis

초록

In the context of intensifying U.S.–China strategic competition in the Indo–Pacific, the security of the Korean Peninsula and the Taiwan Strait are inextricably linked. A simultaneous two-front crisis in these subregions would pose a grave threat to regional stability, as China and North Korea could coordinate to exploit vulnerabilities in the United States and allied postures—triggering a “strategic balloon effect” that undermines deterrence. However, the current framework for trilateral security cooperation among the Republic of Korea (ROK), the United States, and Japan lacks both a pre-coordinated response mechanism and clear operational guidelines for managing concurrent contingencies. These structural gaps hinder the alliance network’s ability to effectively deter or respond to a two front crisis. While establishing a formal unified command structure, that includes the Korean Peninsula Theater and the Taiwan Strait Theater, remains politically and historically unfeasible, this paper proposes a “de facto one-theater” strategy to strengthen trilateral operational security cooperation without formal integration of theaters. This strategy focuses on diplomatic coordination to institutionalize a shared threat perception of a potential two-front crisis, conducting joint exercises tailored to simultaneous contingencies with a view to enhancing trilateral interoperability, and expanding multi-domain cooperation—particularly in nuclear, cyber, and space domains—to develop integrated operational capabilities. By advancing these measures under a de facto one-theater framework, the ROK, United States, and Japan can close critical response gaps, develop a coherent and unified response strategy, and establish a more credible deterrent posture against the growing threat of a coordinated two-front contingency in the Indo–Pacific.

키워드