CAMP MAKOMANAI, Japan – Col. Kenji Sawai, commander of Japan's 18th Infantry Regiment, stands in his headquarters dressed from head to foot in white camouflage. Skis clutter the hallways of his outpost in the snow-covered mountains of northern Japan, along with stacks of white ponchos, gloves and boots.

For decades, the mission for Japanese officers such as Sawai has been fairly straightforward: Defend the homeland. Narrowly defined, for Sawai and his infantrymen, that means protecting the island of Hokkaido, where the regiment is based, from invasion.

Now that definition is changing.

The political leadership and military planners — with the blessing of Washington, their closest ally — are cautiously moving the military away from its longtime role as a stay-at-home force. The new stance, while still centered on national defense, allows troops to be sent all over the world for a broad range of operations.

Lawmakers are mulling calls from the United States for Tokyo to send "boots on the ground" to bolster President Barack Obama's stepped-up efforts to bring peace to Afghanistan. The U.S. has said that it would welcome a dispatch of soldiers.

While such a move would set off controversy among the public and is unlikely anytime soon, the government has taken a number of steps that would have been unthinkable a decade ago. It sent 600 troops to Iraq, albeit in a noncombat role; it has a refueling mission in the Indian Ocean that supports U.S. forces in Afghanistan; and it has sent two naval ships to the waters off Somalia to help battle pirates.

The tentative transition is reshaping the balance of power in northeast Asia — one of the world's most volatile and heavily armed regions — and could be a key to Japan's security as China's military rises and North Korea continues to be a nuclear-capable wild card.

Sawai's remote command, a series of drab beige barracks surrounded by sprawling marching fields, is already seeing the trickle-down effect.

At this year's "North Wind" exercises, annual maneuvers held with the United States, U.S. commanders said training involved more joint attacks, more collaboration, closer command and control — just the kind of thing that would be needed if the Japanese were to be fighting alongside the U.S. in Iraq or Afghanistan.

"We have never actually been to war, and there are many things that we want to learn from the U.S. soldiers," Sawai said after addressing his troops and several hundred U.S. National Guard soldiers who came to his base from Kentucky for the 11-day maneuvers.

It was a striking contrast: Many of the American guardsmen have been sent to war zones two or three times, while no Japanese soldier has fired a bullet in combat since Tokyo's 1945 surrender ended World War II — thanks largely to a pacifist constitution written by U.S. occupiers to keep Japan from rearming.

Sawai stressed that the exercises were not directly intended to ready the Japanese for deployment overseas.

"Defense is our mission," Sawai said. "That has not changed."

Still, the new, more aggressive, role of Japan's military is hard to ignore.

Japan has about 240,000 uniformed troops, with about 130,000 of them in the army, which is formally known as the Ground Self-Defense Forces. Because of sensitivities left over from the last century, the military itself is known as the Self-Defense Force.

Constitutional restrictions have barred the military from acquiring an aircraft carrier or some air-to-air refueling capabilities needed for long-range strikes, which are crucial for the projection of force but are considered too aggressive to meet the constitutional defense-only rules. Unlike China's double-digit defense spending growth, Japan's has remained flat for years. China has for years outspent Japan — $70 billion to $49 billion in 2009.

Even so, Japan has one of the best-funded and highly regarded militaries in the world. Its navy, in particular, is regarded as the best operating in the region, after only the U.S. Navy.

Earlier this month, after much haggling in parliament, two Japanese naval destroyers were dispatched to the sea off Somalia to join the multinational fight against piracy. Two more destroyers were sent to the Sea of Japan to monitor North Korean missile activity. And late last year, Japanese troops ended a four-year humanitarian and airlift mission in Iraq, the military's biggest overseas operation since World War II.

On the home front, Japan has worked closely with the United States to erect a multi-billion dollar ballistic missile shield to protect the country — and the 50,000 U.S. troops stationed here — from a potential attack by its unpredictable and often belligerent neighbor, North Korea.

Elements of that shield could soon be tested if North Korea, as expected, test launches its first long-range ballistic missile since a failed attempt in 2006. North Korea claims the launch is intended to put a satellite into orbit, but Japanese officials have said they are prepared to respond if the missile's trajectory poses a threat to Japan's territory.

Sending troops to Afghanistan or elsewhere would likely stir up opposition from many Japanese who recall the disaster of the previous century's militarist misadventures and strongly resist any action that might lead Japan again into war.

"I would anticipate the SDF (Japanese Self-Defense Force) taking a significantly larger role on the international stage in the years to come. There are any number of international and domestic factors that all point in the same direction on this point," said Eric Heginbotham, a political scientist with the U.S.-based RAND Corporation.

But raising the question of Japan sending troops to Afghanistan, he added: "I would say it is unlikely, unless the situation there stabilizes or the SDF can identify a safe corner of the country in which to operate. Japan is still extremely casualty sensitive."

Japan's neighbors are also wary of such moves.

But political opposition at home is eroding. Japan's two biggest parties both advocate the country taking a higher-profile role on the world stage, largely for nationalistic reasons. And the new mood dovetails with pressure from the United States, which would welcomes a stronger Japan that could assist thinly spread U.S. forces and serve as a counterbalance to the growing military strength of China.

"Gradually, Japan is moving toward that direction," said Tsuneo Watanabe, a senior fellow at the Tokyo Foundation.

"There is vague consensus among the policy circle. However, there is no consensus among ordinary citizens and politicians," he said. "The bridging role should be played by politicians, the policy research community and media."

(Agencies)