Despite Shigemitsu's well-known opposition to the war, at the insistence of the Soviet Union, he was taken into custody by the
Supreme Commander of the Allied Powers and held in
Sugamo Prison as an accused
war criminal. Despite a signed deposition by
Joseph Grew, the former ambassador of the United States to Japan, over the protests of
Joseph B. Keenan, the chief prosecutor, Shigemitsu and his case came to trial and was convicted by the
International Military Tribunal for the Far East for waging an aggressive war and for not doing enough to protect
prisoners-of-war from inhumane treatment. However, the tribunal was extremely lenient on the grounds that Shigemitsu had regularly opposed Japanese militarism and protested the POWs' inhumane treatment. He was sentenced to seven years in prison, the lightest punishment that was handed down to anyone convicted at the trial. He was paroled in 1950. After the end of the
occupation of Japan, Shigemitsu formed a short-lived political party,
Kaishintō, which merged with the
Japan Democratic Party in 1954. In October 1952, he was elected to a seat in the
Lower House of the
Diet of Japan, and in 1954, he became
Deputy Prime Minister of Japan under Prime Minister
Ichirō Hatoyama, the leader of Japan Democratic Party. The cabinet continued after the merger of the party and the
Liberal Party as the
Liberal Democratic Party (LDP) in 1955, and Shigemitsu continued to hold the post of
Deputy Prime Minister of Japan until 1956. Shigemitsu concurrently served as
Foreign Minister from 1954 to 1956. In April 1955, he represented Japan at the
Bandung Conference held in
Indonesia, which marked the beginning of the return of Japan to participating in an international conference since the
League of Nations. Then in August, Shigemitsu led a high-level Japanese delegation to the United States to press for a revision to the
U.S.–Japan Security Treaty, but this effort was met with a cold reception from Secretary of State
John Foster Dulles, who had been the treaty's primary architect and was loath to revisit it. Dulles told Shigemitsu in no uncertain terms that any discussion of treaty revision was "premature" because Japan lacked "the unity, cohesion, and capacity to operate under a new treaty arrangement," and Shigemitsu was forced to return to Japan empty-handed. The following year, Shigemitsu addressed the
United Nations General Assembly, pledging Japan's support of the founding principles of the
United Nations and formally applying for membership. Japan became the UN's 80th member on December 18, 1956. Shigemitsu also travelled to
Moscow in 1956 in an attempt to normalize diplomatic relations and to resolve the
Kuril Islands dispute. The visit resulted in the
Soviet–Japanese Joint Declaration of 1956. ==Death==