At a conference held in Moscow in Dec., 1945, the victorious allied powers of the Second World War agreed to an international effort to reconstruct the Japanese state along democratic lines. U.S. Gen. Douglas MacArthur, commander of U.S. forces in Japan, was granted authority to "issue all orders for the implementation of the Terms of Surrender, the occupation and control of Japan, and all directives supplementary thereto," and for seven years, the United States maintained an occupation force in the country that oversaw comprehensive reforms of the country's military, economy, politics, and society.

To uproot the militarism that had pervaded Japanese government, the Supreme Command of Allied Powers (SCAP) began by dismantling and disarming the Japanese armed forces and between May 1946 and Nov. 1948, they held an International Military Tribunal that tried nine senior political leaders and eighteen military leaders for war crimes. Subsequent efforts to reconstruct the state included land reforms intended to blunt the power of traditional elite, a thoroughgoing restructuring of industry and the economy to align it with western market capitalism, and the imposition of new pacifist constitution that shifted power from the Emperor to parliament. With the rise of the Cold War and change in international priorities, the U.S. brokered a final peace settlement with Japan that formally ended the occupation in 1952, leaving most American military bases and a bilateral security pact intact.