Beyond the Peninsula: Evolving Strategic Logic of United States Forces Korea

This thesis examines the evolving strategic rationale of United States Forces Korea (USFK) within the broader context of the U.S.–ROK alliance and the Indo-Pacific security landscape. While the alliance was originally established in 1953 to counter North Korea’s conventional military threat, its purpose has undergone significant transformation over the past seven decades. In particular, this study argues that USFK’s role has shifted from a peninsula-focused deterrent to a regional platform aimed at balancing China’s rise. Through a three-part analysis, the paper first traces the historical development of the alliance and reviews existing literature on alliance politics and threat perception. It then introduces the hypothesis of a strategic shift and analyzes three key developments—the deployment of Terminal Height Altitude Area Defense (THAAD) in Seongju, the termination of South Korea’s missile range guidelines, and the relocation of USFK headquarters—as evidence of an evolving mission. The final section addresses potential counterarguments, including the continued threat posed by North Korea, and concludes that China’s increasingly assertive posture has become the primary driver of alliance recalibration. By highlighting the gap between diplomatic rhetoric and operational planning, this study contributes to a more nuanced understanding of alliance adaptation in an era of intensifying great-power competition.