歐巴馬與川普政府美、日、韓三邊「準同盟」關係之研究（2009-2019）

2009-2019年間，隨著美國調整其外交政策，試圖鞏固並提升其在亞太地區的領導地位與影響力，連帶影響了其與東亞兩大盟國日本及南韓的同盟關係。學者車維德（Victor Cha）在1999年所提出的假說指出，當美國外交政策調整而影響其所給予盟國的安全承諾強度時，出現關係變化的不僅有美國與日、韓之間的同盟關係，更包括了日本與南韓之間特殊的「準同盟關係」，透過文獻分析法檢視與探討歐巴馬與川普兩位總統任期之中美國、日本、南韓之間的互動關係，本文將論證美國的安全承諾強度變化是否仍舊深刻影響著日本與南韓之間的雙邊關係，同時描繪三國同盟與準同盟關係中共同威脅認知產生變化的主因。本論文藉由與車氏的假說對話，探討其假說是否仍將適用於近十年及未來的美、日、韓三國互動關係。本論文發現，在共同威脅認知產生變化的情況下，車氏的假說之解釋力將下降。

關鍵字

美國東亞外交；美日同盟；美韓同盟；日韓關係；準同盟

並列摘要

During 2009 to 2019, the United States had adjusted its foreign policy in order to solidify its leading position and increase its influence in Asian-Pacific region. Such adjustment brought out impacts on its major allies in East Asia - Japan and South Korea. According to the theoretical hypothesis of Victor Cha(1999), if the United States changes its foreign policy and affects the strength of security commitment toward its allies, not only the relation between the United states with Japan/Korea will be altered, the “quasi-alliance” relation between Japan and Korea will also be influenced. Utilizing document analysis，the dissertation will analyze the triangular interaction between the United States, Japan and Korea during the term of Obama and Trump, and argue that whether the strength of security commitment is still a prominent factor of the bilateral relation between Japan and Korea, with description on the major cause of the shifting cognition on common threat of the triangular alliance and the quasi-alliance. The dissertation explores Cha’s theory and investigates whether it can still apply toward the United States-Japan-Korea interaction in the past decade and future ; the dissertation finds out that with the change of cognition of common threat, the explanation power of Cha’s theory may be undermined.