By Linda Sieg
TOKYO (Reuters) - Japan's cabinet is expected on Tuesday to end a ban that has kept the military from fighting abroad since World War Two, a major shift away from post-war pacifism and a political victory for Prime Minister Shinzo Abe who has pursued the change despite some public opposition.
The move, seen by some as the biggest shift in defence policy since Japan set up its post-war armed forces in 1954, would end a ban on exercising "collective self-defence", or aiding a friendly country under attack.
It would also relax limits on activities in U.N.-led peace-keeping operations and "grey zone" incidents that fall short of full-scale war, according to a draft cabinet resolution.
Long constrained by the pacifist post-war constitution, Japan's military would be more closely aligned with other advanced nations' armed forces in terms of its options to act, though the government would likely remain wary of putting boots on the ground in multilateral operations such as the 2003 U.S.-led invasion of Iraq.
"It's a dimensional change," said former Japanese diplomat Kunihiko Miyake. "We have lived in the world of the second dimension, now we are entering a third dimension ? which is the global standard."
Abe has pushed for the change since taking office 18 months ago despite wariness among many Japanese voters worried about entanglement in foreign wars and angry at what some see as a gutting of the constitution's war-renouncing Article 9.
A group of several thousand protesters, including students and pensioners, marched in front of the prime minister's office on Monday carrying banners and shouting, "I don't want to see our children and soldiers die" and "protect the constitution".
A day earlier, a man set himself on fire near a busy Tokyo intersection - a rare form of protest in Japan - after speaking out against Abe's re-interpretation of Article 9.
The change will also likely rile an increasingly assertive China, whose ties with Japan have frayed due to a maritime row, mistrust and the legacy of Japan's past military aggression.
It will, however, be welcomed by Washington which has long urged Tokyo to become a more equal partner in their alliance.
Parties in Abe's ruling coalition are expected on Tuesday morning to agree to the proposed lifting of the ban on collective self-defence, paving the way for cabinet later in the day to adopt a resolution revising a long-standing interpretation of the U.S.-drafted constitution.
Legal revisions to implement the change must be approved by parliament and restrictions could be imposed in the process.
Since its defeat in 1945, Japan's military has not engaged in combat. While successive governments have stretched the limits of the pacifist charter to develop a military now on par with that of France and to permit non-combat missions abroad, its armed forces remain far more constrained legally than those of other nations.
Conservatives say the constitution's Article 9 has excessively restricted Japan's ability to defend itself and that a changing regional power balance, including a rising China, means Japan's security policies must be more flexible.
The policy shift is seen by many experts as the latest step by Japan toward becoming a "normal nation" with its military less circumscribed by its pacifist constitution.
China, however, will likely argue Japan is raising regional tensions and support its case by pointing to Abe's efforts to cast Tokyo's wartime past with a less apologetic tone. Some experts agree Abe's revisionist image makes him vulnerable to suspicions that he has a deeper nationalist agenda.
"It makes it easier for competitors to paint Japan as a wolf in sheep's clothing," said Richard Samuels, director of the Center for International Studies at the Massachusetts Institute of Technology. "Just because Japan is strong does not mean that it will be aggressive," he added.
According to a draft cabinet resolution made public last week, Japan could exercise force to the minimum degree necessary in cases where a country with which it has close ties is attacked and the following conditions are met: there is a threat to the existence of the Japanese state, there is a clear danger that the people's right to life, liberty and the pursuit of happiness could be subverted, and there is no appropriate alternative.
Precisely how the change might work in practice remains unclear. Junior coalition partner New Komeito is stressing that the scope of revision is limited, and Japanese voters are still wary of entanglements in conflicts far from home.
"I only see this happening in areas near Japan. I don't see Japan deploying far-away forces in the context where they end up in the front-lines," said Brad Glosserman, executive director of the Honolulu-based Pacific Forum CSIS.
(Editing by Mark Bendeich and Dean Yates)