朝鮮半島と日米安全保障条約-日米韓連鎖構造の形成-

日米安保体制-持続と変容

抄録

American policy toward Korea, as followed by the administrations of Presidents Harry S. Truman and Dwight D. Eisenhower, was shaped in the face of a continuous dilemma caused by the two distinct evaluations of the situation in the Korean Peninsular. One of these was a strategic evaluation of the necessity for a reduction or elimination of the US military commitment to South Korea based on the belief that Korea was not strategically important in terms of the overall struggle with the USSR, and the other was a political evaluation of the need to avoid the adverse political ramifications in the Far East and the rest of the world should Korea fall to the communist bloc following an American withdrawal.
Following the outbreak of the Korean War, the Truman administration entered the war as part of the UN forces under the terms of the UN's collective security system. This decision was a reflection not only of a political necessity to prevent the Korean Peninsular from falling to the communists but also of the American Government's desire to avoid an independent US military commitment in Korea. In addition, the subsequent decision of the Eisenhower administration to conclude a mutual defence treaty with South Korea, which resulted in an expansion of the US military commitment in Korea, was designed to achieve the participation and cooperation of the administration of Syngman Rhee in the armistice negotiations, a process the South Koreans had been opposing.
Meanwhile, Japan assumed a position of crucial importance in US Far Eastern policy as a bulwark against futher communist expansion. America sought Korean neutrality as this would make it possible to reduce or terminate its military commitment in the peninsular. However, at the same time, by negotiating the Japan-US Security Treaty, America aimed not only to guarantee Japan's place in the anticommunist world but also to open up the possibility of Japanese rearmament and hopefully to obtain Japanese contribution to the defense of freedom in the Pacific region.
However, the Japanese government refused American requests to build up its military potential because of factors such as its economic fragility and the contemporary domestic political situation. Ultimately America was left with no choice but to adopt a policy of emphasizing political and economic stability in Japan instead. Meanwhile, the political conference with Communist China and North Korea broke down and the plan for a neutral Korea collapsed, with the result that the division of Korea into North and South remained unchanged. As a consequence, the US started to consider, instead of Japan, South Korea, which was developing into a military power, as a potential contributor to the security in the Far East.
As a result, it could be argued that South Korea has taken on Japan's security obligations, while Japan now tends to consider South Korea essential in terms of its own security. At the same time, relations between Japan and S. Korea have become susceptible to any change in the US military strength in the Far East.