「芦田書簡」の再検討

――有事駐留構想と警察改革の連関を中心に――

抄録

Focusing on the Ashida Memorandum, this article examines the rise and fall of Japan’s security plan to station US military forces in Japan in the case of emergency. On September 13, 1947, Ashida Hitoshi, the Vice Prime Minister and the Foreign Minister of the Katayama cabinet, in cooperation with high officials of the Foreign Ministry, submitted a memorandum on Japan’s security to Robert L. Eichelberger, the Commander of US 8th Army. This memorandum, while stating security cooperation between the United States and Japan, argued to secure Japan’s independence through US military forces stationing in islands surrounding Japan’s mainland in peacetime. Nevertheless, the Japanese government, after the submission of the memorandum, decided to request the maintenance of US forces in Japan even after the peace settlement. This article, using hitherto used and newly declassified primary sources of Japanese foreign and police officials, and paying attention to the impact of the police reform of late 1947, reconsiders the historical process up to the formation of post-war Japan’s security policy.

Ashida and high officials of the Foreign Ministry, assuming US military forces would be withdrawn from Japan’s mainland after the peace settlement, sought to get a permission from GHQ regarding the reinforcement of Japan’s police forces to deal with internal communist threats. The Supreme Commander Douglas MacArthur showed a positive stance toward Ashida’s attempt. On September 3, he told the Japanese government that the Japanese police forces would be strengthened. Based on this information, Ashida and MOFA staff worked out the plan of emergency stationing of US forces. In other words, in the background of the submission of the Ashida Memorandum, there was an optimistic expectation that GHQ would permit the strengthening of the Japanese police forces in advance of the peace settlement.

Nevertheless, simultaneous with the submission of this memorandum, due to the change of MacArthur’s stance, GHQ chose the large-scale de-centralization of the Japanese police system as the principle of the police reform. Therefore, on September 17, GHQ directed the Japanese government to initiate this reform. In contrast to MOFA’s expectation, due to the establishment of the new Police Law in late 1947, Japan’s internal security capability was largely restricted. In these circumstances, the Japanese government was forced to depend on US military forces to maintain Japan’s internal security. Therefore, Yoshida Shigeru, after coming into power in late 1948, chose to deal with internal communist threats by maintaining US military presence in Japan’s mainland. Through examining the interrelation between internal and external issues, this article argues that internal security calculation was an important rationale behind the formation of the postwar US-Japan security partnership.