Constitution of Japan

The Constitution of Japan is the supreme law of Japan. Written primarily by American civilian officials during the occupation of Japan after World War II, it was adopted on 3 November 1946 and came into effect on 3 May 1947, succeeding the Meiji Constitution of 1889. The constitution consists of a preamble and 103 articles grouped into 11 chapters. It is based on the principles of popular sovereignty, with the Emperor of Japan as the symbol of the state; pacifism and the renunciation of war; and individual rights.

Upon the surrender of Japan at the end of the war in 1945, Japan was occupied and U.S. General Douglas MacArthur, the Supreme Commander for the Allied Powers, directed Prime Minister Kijūrō Shidehara to draft a new constitution. Shidehara created a committee of Japanese scholars for the task, but MacArthur reversed course in February 1946 and presented a draft created under his own supervision, which was reviewed and modified by the scholars before its adoption. Also known as the "MacArthur Constitution", "Post-war Constitution" (戦後憲法, Sengo-Kenpō), or "Peace Constitution" (平和憲法, Heiwa-Kenpō), it is relatively short at 5,000 signs, less than a quarter the length of the average national constitution if one compares it with constitutions written in alphabetical word-based languages.

The constitution provides for a parliamentary system and three branches of government, with the National Diet (legislative), Cabinet led by a Prime Minister (executive), and Supreme Court (judicial) as the highest bodies of power. It guarantees individual rights, including legal equality; freedom of assembly, association, and speech; due process; and fair trial. In contrast to the Meiji Constitution, which invested the emperor with supreme political power, under the 1946 constitution his role in the system of constitutional monarchy is reduced to "the symbol of the State and of the unity of the people", and he exercises only a ceremonial role under popular sovereignty. Article 9 of the constitution renounces Japan's right to wage war and to maintain military forces. Despite this, it retains a de facto military in the form of the Self-Defense Forces and hosts a substantial U.S. military presence. Amendments to the constitution require a two-thirds vote in both houses of the National Diet and approval in a referendum, and despite the efforts of conservative and nationalist forces to revise Article 9 in particular, it remains the world's oldest un-amended supreme constitutional text.

The Meiji Constitution was the fundamental law of the Empire of Japan, propagated during the reign of Emperor Meiji (r. 1867–1912). It provided for a form of mixed constitutional and absolute monarchy, based on the Prussian and British models. In theory, the Emperor of Japan was the supreme leader, and the cabinet, whose prime minister was elected by a privy council, were his followers; in practice, the Emperor was head of state but the Prime Minister was the actual head of government. Under the Meiji Constitution, the prime minister and his cabinet were not accountable to the elected members of the Imperial Diet, and increasingly deferred to the Imperial Japanese Army in the lead-up to the Second Sino-Japanese War.

On 26 July 1945, shortly before the end of World War II, Allied leaders of the United States (President Harry S. Truman), the United Kingdom (Prime Minister Winston Churchill), and the Republic of China (President Chiang Kai-shek) issued the Potsdam Declaration. The Declaration demanded Japanese military's unconditional surrender, demilitarisation and democratisation.

The declaration defined the major goals of the post-surrender Allied occupation: "The Japanese Government shall remove all obstacles to the revival and strengthening of democratic tendencies among the Japanese people. Freedom of speech, of religion, and of thought, as well as respect for the fundamental human rights shall be established" (Section 10). In addition, "The occupying forces of the Allies shall be withdrawn from Japan as soon as these objectives have been accomplished and there has been established in accordance with the freely expressed will of the Japanese people a peacefully inclined and responsible government" (Section 12). The Allies sought not merely punishment or reparations from a militaristic foe, but fundamental changes in the nature of its political system. In the words of a political scientist Robert E. Ward: "The occupation was perhaps the single most exhaustively planned operation of massive and externally directed political change in world history."

The Japanese government, Prime Minister Kantarō Suzuki's administration and Emperor Hirohito accepted the conditions of the Potsdam Declaration, which necessitates amendments to its Constitution after the surrender.

The wording of the Potsdam Declaration—"The Japanese Government shall remove all obstacles ..."—and the initial post-surrender measures taken by MacArthur, suggest that neither he nor his superiors in Washington intended to impose a new political system on Japan unilaterally. Instead, they wished to encourage Japan's new leaders to initiate democratic reforms on their own. But by early 1946, MacArthur's staff and Japanese officials were at odds over the most fundamental issue, the writing of a new Constitution. Emperor Hirohito, Prime Minister Kijūrō Shidehara, and most of the cabinet members were extremely reluctant to take the drastic step of replacing the 1889 Meiji Constitution with a more liberal document.