TOKYO (Reuters) - A likely win by Shinzo Abe's Liberal Democrats in this weekend's election will give the ex-Japanese premier a second chance to achieve his goal of easing the limits of a pacifist constitution on the military to let Tokyo play a bigger global security role.
Surveys released on Tuesday showed the conservative Liberal Democratic Party and its ally are headed for a big victory in Sunday's vote for parliament's lower house, returning them to power after a three-year gap.
As prime minister in 2006-2007, Abe made revising the 1947 constitution a key part of a drive to shed a U.S.-imposed "post-war regime" that conservatives say weakened traditional values and fostered too apologetic a view of Japan's wartime history. He still hopes to achieve what he has called his "life work".
Growing worries about China's military clout mean conditions are better than before for changing how the U.S-drafted charter is interpreted - if not formally rewriting the document yet - to let Tokyo drop a self-imposed ban on exercising its right to collective self-defence, or aiding an ally under attack.
That would allow Japan's military to shoot down a North Korean missile headed for U.S. cities, come to the aid of a U.S. vessel under attack on the high seas and generally ease the path for joint operations with U.S. forces, experts say.
"I think changing the interpretation is relatively easy procedurally and substantially and in terms of mood, it is the right atmosphere," said Richard Samuels, director of the Center for International Studies at the Massachusetts Institute of Technology in Boston, an expert in Japan's security policies.
"He will do it because he can. The stars are aligned for that kind of shift sooner rather than later."
The constitution's Article 9 renounces the right to wage war to resolve international disputes and, if taken literally, bans the maintenance of a military.
But it has already been stretched to allow the maintenance of a military for self-defence as well as overseas activities, including troop deployment on a non-combat mission to Iraq.
Further moves, even if in some ways symbolic, would trigger outrage in China, where memories of Japan's wartime aggression run deep. A feud over rival claims to tiny islands in the East China Sea this year sparked violent protests and boycotts of Japanese firms, damaging trade between the region's two biggest economies.
"Right-wing tendencies in Japan are currently very strong, and Abe is acting on this. Looking at Japan now, it's not that likely that it will revive militarism, but if it alters the constitution, it will give Japan a chance to strengthen its military weaponry," said Huang Dahui, a professor and Japan specialist at People's University in Beijing.
"It presents an opening for there to be no restrictions. So in the long run, I think we need to be vigilant toward Japan."
The changes would be welcome in Washington, which has long urged Tokyo to take on more of the alliance burden, and in parts of Asia, although any efforts to recast Japan's wartime history in less apologetic terms would be less so.
The Philippines said on Monday that a stronger Japan would act as a counterbalance to China's military rise, which is worrying smaller Asian nations as tensions grow over rival territorial clains in the South China Sea.
"If moving to the right means increasing defence spending and getting rid of obsolete barriers to more effective defence cooperation with the U.S., then my answer to that is 'bring it on'. We absolutely welcome it and so does almost the entire Southeast Asia - not just the Philippines," said Michael Green at the Washington-based Center for Strategic and International Studies.
Abe has also pledged to increase defence spending after a decade of decline, which would probably break through a de facto cap of 1 percent of GDP in place for decades.
"If moving to the right means gratuitous and not very smart moves, like revisiting the Kono statement, that's a problem for the U.S. ... not as a moral issue, but as a realpolitik issue."
Abe favours revising a 1993 statement by then-top government spokesman Yohei Kono, in which Japan admitted military involvement in forcing women into sexual slavery at wartime brothels, although he now says he would seek experts' views first.
The constitution, drafted by U.S. Occupation authorities during a frantic week in February 1947, has never been altered.
Revisions require approval by two-thirds of the members of both houses of parliament and a majority of voters in a national referendum. Changing the interpretation, however, can be done without legislation, so Abe will likely try that first.
Still, the prospect of an election for parliament's upper house in July 2013 could persuade Abe to go slow to avoid upsetting the LDP's long-time partner, the more moderate New Komeito party.
"The next thing (on the agenda) is not the constitutional interpretation, the next thing is the upper house election next summmer," said Kunihiko Miyake, a former diplomat who is now research director at the Canon Institute for Global Studies in Tokyo.
"If you go too fast, it could have repercussions."
But he added: "It will be on the agenda sooner or later because this is the minimum level of required policy change to make our alliance (with the United States) and international peacekeeping operations more effective and credible."
Advocates of revising the charter say it has now been stretched to the limit so formal changes are needed both to make joint operations with U.S. forces easier and perhaps open the door to NATO-style security treaties with other countries.
A March 2012 survey by the conservative Yomiuri newspaper showed 54 percent of voters wanted some change to the charter, the first time that figure exceeded half since 2009.
Thirty-nine percent favoured revising Article 9, while the same percentage said changing the interpretation was enough.
Many members of the ruling Democratic Party, expected to suffer a bashing at the polls, favour revising the constitution, but the party has been divided on the topic.
Abe managed during his last term to get parliament to enact procedures for a referendum, and he set up an experts' panel to outline scenarios where Japan should aid its ally.
But he quit for health reasons before the panel submitted the report and his more dovish successor shelved it.
Abe and his backers have made clear that their first target would not be Article 9 itself but a separate article spelling out the need for the two-thirds majority in both houses of parliament to enact revisions. They want to reduce that hurdle to a simple majority so that subsequent changes are easier.
Whether Japan's unstable political scene will allow Abe to stay in power long enough to achieve his goal is far from clear.
Japan has already had six prime ministers since 2006. All have seen their public ratings sink in a matter of months.
Abe could suffer the same fate.
"If the past is prologue, it (the decline in ratings) will be a pretty steep slope," Samuels said.
Editing by Ron Popeski