The Policy Of The Korean Peninsula In The Period Of Truman Administration (1945-1950)

In January1950President Truman and Acheson issued speeches respectively to preclude Korean Peninsular from American protection. However, on25June1950, when the Korean War broke out, American intervened militarily and immediately under the flag of UN. This thesis tries to explain an important but uncovered issue, that is, why Truman and Acheson preclude American protection of Korean peninsula in the defense speech in January1950despite of a fact that PRC was founded and USSR exploded the first atom bomb in1949? But when the Korean War broke out, it intervened militarily and immediately?This thesis tries to demonstrate that from the end of World War Two to "defense speech", Truman administration has developed into a perception that Korean Peninsula is important to American national interest via the flexible relations between national interest and national power. Thus Truman administration has tried several times to unify the Korean Peninsula under a government favorable to American government. However, the limited national power and the expansive commitment confined the American national interest. It can achieve and lead it to pursue a lower objective in Korean Peninsula, namely avoiding the whole peninsula to become communism. During this period, America used economic aid, dispatch of military advisory groups as main means to maintain the survival of south peninsula.On the other hand, basing on the above policy objective, the catalyst which led America to intervene militarily instead of aiding indirectly lay in domestic and international changes from February1950to June1950. These changes embodied in Sino-USSR allies’pact, McCarthyism and the beginning of the full containment policy of the US. These caused America to alter its strategy, namely the means supporting its national interests, and emphasize the military means to contain the expansion of communism.