On May 3, 1947, Japan’s postwar constitution goes into effect. The progressive constitution granted universal suffrage, stripped Emperor Hirohito of all but symbolic power, stipulated a bill of rights, abolished peerage, and outlawed Japan’s right to make war. The document was largely the work of Supreme Allied Commander Douglas MacArthur and his occupation staff, who had prepared the draft in February 1946 after a Japanese attempt was deemed unacceptable.

As the defender of the Philippines from 1941 to 1942, and commander of Allied forces in the Southwest Pacific theater from 1942 to 1945, Douglas MacArthur was the most acclaimed American general in the war against Japan. On September 2, 1945, aboard the USS Missouri in Tokyo Bay, he presided over the official surrender of Japan. According to the terms of surrender, Emperor Hirohito and the Japanese government were subject to the authority of the Supreme Commander for Allied Powers in occupied Japan, a post filled by General MacArthur.

On September 8, Supreme Commander MacArthur made his way by automobile through the ruins of Tokyo to the American embassy, which would be his home for the next five and a half years. The occupation was to be a nominally Allied enterprise, but increasing Cold War division left Japan firmly in the American sphere of influence. From his General Headquarters, which overlooked the Imperial Palace in central Tokyo, MacArthur presided over a reconstruction of Japanese government, industry, and society along American models. MacArthur was a gifted administrator, and his progressive reforms were for the most part welcomed by the Japanese people.

The most important reform carried out by the American occupation was the establishment of a new constitution to replace the 1889 Meiji Constitution. In early 1946, the Japanese government submitted a draft for a new constitution to the General Headquarters, but it was rejected for being too conservative. MacArthur ordered his young staff to draft their own version in one week. The document, submitted to the Japanese government on February 13, 1946, protected the civil liberties MacArthur had introduced and preserved the emperor, though he was stripped of power. Article 9 forbade the Japanese ever to wage war again.

Before Japan’s defeat, Emperor Hirohito was officially regarded as Japan’s absolute ruler and a quasi-divine figure. Although his authority was sharply limited in practice, he was consulted with by the Japanese government and approved of its expansionist policies from 1931 through World War II. Hirohito feared, with good reason, that he might be indicted as a war criminal and the Japanese imperial house abolished. MacArthur’s constitution at least preserved the emperor as the “symbol of the state and of the unity of the people,” so Hirohito offered his support. Many conservatives in the government were less enthusiastic, but on April 10, 1946, the new constitution was endorsed in popular elections that allowed Japanese women to vote for the first time. The final draft, slightly revised by the Japanese government, was made public one week later. On November 3, it was promulgated by the Diet—the Japanese parliament—and on May 3, 1947, it came into force.

In 1948, Yoshida Shigeru’s election as prime minister ushered in the Yoshida era, marked by political stability and rapid economic growth in Japan. In 1949, MacArthur gave up much of his authority to the Japanese government, and in September 1951 the United States and 48 other nations signed a formal peace treaty with Japan. On April 28, 1952, the treaty went into effect, and Japan assumed full sovereignty as the Allied occupation came to an end.