南韓及美國自1953年的《共同防禦條約》、1968年的安全協商會議及1978年成立之聯合軍事指揮部，形成現存的美韓軍事同盟。兩國在冷戰期間，基於軍事、經濟及政治不同戰略立場，美國希冀在朝鮮半島建立一個以美國為核心的安全與合作機制；南韓則盼在政治穩定及軍事保護之下發展國內經濟產業，因此美韓同盟得以順利運作並鞏固60年。然而，南韓政府在國內面臨反美聲浪、北韓武力威脅、撤軍聲浪；對外，又適逢中國強勢崛起、區域強權環境更迭等議題，使得冷戰期間即已建立之同盟關係面臨挑戰。本文試圖從StephenWalt所提之同盟理論中，有關影響同盟之四項威脅因素：整體國力、地理位置、攻擊侵略能力及侵略意圖，進行交叉分析，另外，本文也引介Glenn Snyder的同盟安全困境理論，藉由其中三項影響政府參與同盟之變項：利益、依賴、承諾，綜合分析美韓同盟的可能走向。

The existing military alliance between the United States and South Korea has evolved from the ＂Mutual Defense Treaty between the United States of America and the Republic of Korea＂ in 1953 to the ＂Security Consultative Meeting＂ in 1968, and then to the ＂USROK Combined Forces Command＂ in 1978. During the Cold War, the United States government attempted to establish an American-centered mechanism of security and cooperation in the Korean Peninsula, whereas South Korea wanted to develop its domestic economy under an environment of political stability and military protection. Therefore, given the strategic considerations of the military, economy, and politics, the US- ROK alliance has undergone steady development for 60 years. However, this relationship has been challenged in recent years because of domestic problems in South Korea, such as anti-American sentiments, North Korea's military threat, and calls for the United States to withdraw its troops, as well as international challenges such as the dynamic conditions of China's rise as the region's new dominant power. To analyze the possible future of the US- ROK alliance, two theories are applied in this paper to examine US- ROK relations: Stephen Walt's alliance theory, which specifically addresses the four threats of aggregate power, geographic proximity, offensive power, and aggressive intentions; and Glenn Snyder's alliance security dilemma theory, which involves the three variables of interests, relative dependence, and the degree of commitment, which influence governmental participation in forming alliances.