Article 96 of the Constitution stipulates that any amendment needs to be backed by at least two-thirds of lawmakers in both chambers of the Diet and a majority of support in a national referendum.
But the absence of specific rules for such a national referendum long forestalled attempts to revise the post-World War II Constitution. Indeed, it has never been amended.
Under the first government of Prime Minister Shinzo Abe, a law outlining procedures for a national referendum was enacted in May 2007, 60 years after the Constitution came into effect on May 3, 1947.
Due to a confrontation with opposition parties, the ruling bloc had to railroad the legislation through the Lower House, the more powerful — and important — of the two chambers.
After the U.S. Occupation ended in 1952, a campaign to establish a new Constitution to replace the U.S.-drafted charter gathered momentum. In 1957, a panel of lawmakers and experts was set up by the Cabinet to conduct research on problems with the Constitution.