More than three weeks after a 43-foot-high tsunami wave flattened this town, basic supplies now arrive under the canvas cover of fuming military trucks, property of the 9th Division of Japan’s Ground Self-Defense Forces.

The military vehicles bring fuel from the western side of Japan. They import water in 5,000-liter drums. Soldiers hauled in a camo-colored industrial-size rice cooker. At one evacuation center, they erected a set of tent-covered baths, where survivors could wash away days of built-up dirt. It became the only working shower in town, and for evacuee Ryoko Ohtsubo, who is still missing seven relatives, it lent a daily reprieve that she called “dramatically” life-changing — one indulgence in a place where there had been none.

A pair of natural disasters and an ensuing nuclear crisis turned Japan into a country of unfulfillable needs, but the incidents also created an opportunity for this pacifist nation to rely on its military at a level unseen since World War II.

With local governments fractured and the Tokyo Electric Power Co. ill-equipped for a large-scale disaster, Japan’s Self-Defense Forces have emerged as the backbone of this country’s crisis management. And they have drawn praise from defense experts for their competence as they deliver aid, search for bodies in rubble and perform among the most dangerous tasks at the radiation-leaking Fukushima Daiichi nuclear plant.

The SDF’s precision in this crisis has eroded some of the deep domestic cynicism about the role of — and even the need for — a military that fights only when under attack. Japan is one of the world’s most antimilitarist countries, a legacy of its post-war sensibilities.

Although the SDF performance in crisis management will not transform Japan’s pacifist constitution, it could lead to broader public support for defense spending — particularly as the country faces growing threats from China and North Korea. It could also boost pro-military feelings among younger generations, who have been fed three weeks of media images featuring helmeted men in green.

One widely circulated photo showed a semicircle of SDF troops, on a search mission, praying for a just-recovered victim while standing in frigid, knee-high water. On March 16, low-flying SDF Chinook helicopters dumped saltwater on the overheated reactors at the Fukushima nuclear plant. Later, a half-dozen SDF soldiers in firetrucks equipped with high-pressure hoses sprayed water over the reactors in an effort to cool the overheated spent fuel pools, an unconventional attempt to bring the nuclear emergency under control.

Japan has dispatched 107,000 of its 230,000 troops for disaster relief, and for the first time has established a joint command that coordinates the movements of its ground forces, marines and air force. Its deep involvement — and its coordination with roughly 20,000 U.S. service members — stands in contrast to the 1995 Kobe earthquake, when local government leaders, as well as socialist Prime Minister Tomiichi Murayama, were reluctant to summon the SDF for support.

This time, said Satoshi Morimoto, a national security expert at Takushoku University, the military “is doing everything that local governments are supposed to be doing. Local governments’ disaster plans were based on the assumption that everyone [in the town offices] would survive. But this time, most died in many places. And the local governments are depending on SDF.”

Masateru Muguruma was one of 19,000 SDF members who spent time in Kobe. Now, as the colonel in charge of logistics for the 9th Division, he organizes relief efforts in this town of 23,000, where five of every eight homes was knocked down or damaged. Even the other devastated coastal areas — Kesennuma, Ofunato — still have a skeletal infrastructure, Muguruma said. In Rikuzentakata, “everything is wiped out. We are here to help with survival.”

Forty SDF soldiers spend their days at Yonesaki Elementary School, now a shelter for 800. They hand out towels to bathers, clean the towels at a military-issued washing machine, then fold the towels into crate baskets. They cook meals. Often, they listen to evacuees tell stories about missing family members.

Before March 11, Muguruma had been stationed in Aomori, at the northern tip of Japan’s main Honshu island. Three weeks into this disaster mission, he sees no resolution in sight. “We were prepared for this,” he said, “but I cannot say how long we’ll be here.” And he added: “There is a limit to what we can do.”

The SDF, established in 1954, has developed a reputation for its advanced equipment and its willingness to aid in international peacekeeping. But Japan’s 2011 crisis ranks, easily, as the most complex, protracted mission in SDF history.

Last year, for example, Japan sent 49 members of its military, along with six helicopters, to Pakistan for 11 / 2 months after floods displaced millions. Japan also conducted a mission in Haiti after the January 2010 earthquake, and it launched a disaster-relief effort in Miyazaki prefecture to assist with foot-and-mouth disease.

In his 2011 new year’s address, Defense Minister Toshimi Kitazawa said those efforts helped the SDF “fully demonstrate its capability.”

Only now, though, has the sentiment reached the public. “The cynicism has been dispelled, clearly,” said Sheila Smith, a Japan expert at the Council on Foreign Relations. “The SDF — they’re something to be proud of, and just that sentiment alone is something to acknowledge as important.”

Special correspondent Akiko Yamamoto contributed to this report.