With a revival in nationalism entering Japan's political mainstream, some conservatives believe the time has come to substantially change the constitution enacted while the country was under U.S. military occupation six decades ago.
But many people in Japan and elsewhere in Asia worry it could be the first step toward a re-emergence of the country's militarist past. Much of Asia holds bitter memories of Japanese invasions during the first half of the 20th century.
The most controversial proposal would modify the famous pacifist clause - Article Nine - which forbids Japan from engaging in collective security and places severe restrictions on the country's military.
Japan's self-defense force has almost no ability to fight outside Japanese territory - although it is one of the world's largest armed forces in terms of budget.
Members of the Liberal Democratic Party, a conservative party that leads Japan's ruling coalition, are leading the charge on reform. One of the architects for constitutional change is Yoichi Masuzoe, who says Japan's neighbors should not worry about a resurgence of militarism. He points out that some Asian neighbors have the power to strike at Japan.
"Our F-15 [jet fighter] cannot reach to Pyongyang. We have no aircraft carrier. China has the bomber, fighter. They can reach us easily. North Korea is the same. We are afraid of them," he said. "We have no military capability, so no problem, please [Asia] calm down."
But some are not calm. Many critics of the proposals point to recent friction with China and South Korea over Japanese text books that many think whitewash the imperial era, and over visits by Prime Minister Junichiro Koizumi to a shrine that honors Japan's war dead, including convicted war criminals.
Masahide Ota is a senior figure among Japan's pacifists. A Social Democrat member of the upper house of parliament, he says budding nationalism should raise concern at home and abroad.
"They can argue that even [if] they change the Article Nine, Japan would never go back to the militarism again," said Ota. "But I strongly feel that nationalism of Japan against China and Korea seem to be almost similar to the pre-war days."
One impetus for changing the constitution has been the international push for Japan to take a greater role in world affairs. During the first Gulf War, Tokyo was criticized for contributing money, but being unwilling to take an active military role. Since then, Japan has enacted controversial laws allowing it to send troops abroad for reconstruction and peacekeeping operations.
Politicians across the political spectrum agree that those missions - in such hot spots as Cambodia, the Golan Heights and Iraq - violate at least the spirit of Article Nine. Advocates of reform say they want Japan to become a normal country that has a military and does not need to jump through constitutional loopholes to join peacekeeping efforts.
The reform process is still in early stages. The conservative L.D.P. unveiled an article-by-article draft for constitutional reform last November at its 50th anniversary party.
Party leaders say the next step will be to hold hearings for public input on the draft.
At least two other political parties also intend to draft revision proposals this year.
Such proposals would have been politically impossible a few years ago. Although the L.D.P. has dominated the government for 60 years, its most conservative members could not realize their goal of constitutional reform because of the counter-balance of the leftist opposition.
But the leftists have lost popularity and a centrist party, with many former L.D.P. members, now leads the opposition.
Still, Ota, of the Social Democratic Party, cautions the L.D.P. not to underestimate public support for Article Nine.
"I don't think it's so easy as they claim because nowadays almost 3,000 organization are spreading throughout the country to protect the Article Nine," added Ota. "Japanese people are well aware of the terrible experience they have gone through during the battle of Okinawa and also the Hiroshima and Nagasaki [atomic attacks]. And they cannot forget."
The issue, however, does not appear to raise public passion. In a poll last December, only nine percent selected "constitutional issues" when asked to choose policy issues that the Koizumi government should focus on.
Earlier opinion polls showed that most Japanese want revisions to end the ambiguities about the military's role so Japan can come to the aid of allies. But, at the same time, respondents also say they do not want the pacifist language eliminated.