Originally published Tuesday, March 22, 2011 at 8:45 PM

ON BOARD THE USS RONALD REAGAN — When U.S. Navy helicopters swept down on the school in a ruined Japanese village, survivors first looked hesitantly from the windows. Then they rushed out, helping unload food, water and clothes. They clasped hands with the Americans. Some embraced them.

"They are like gods descending from the sky," said a tearful Junko Fujiwara, 37, a secretary at the elementary-school-turned-shelter in the northern coastal town of Kesennuma. "It's cold and dark here, so we need everything: food, water, electricity, gasoline, candles."

Soon after the devastating earthquake and tsunami struck Japan, the U.S. military began what it calls Operation Tomodachi (Friend), one of its largest relief efforts in recent years. At present, about 20 U.S. ships have massed off Japan's northeastern coast, including the USS Ronald Reagan, a nuclear-powered carrier whose helicopters are busily ferrying supplies to survivors.

That relief is getting through to sometimes difficult-to-reach coastal areas devastated by the March 11 double disaster. They also are the latest showcase in the Pentagon's efforts to use its forces to win goodwill for the U.S. abroad, a strategy that it used successfully in Indonesia after the 2004 tsunami there.

In particular, the United States has grabbed a chance to rebuild ties with a crucial Asian ally that just a year seemed to be flirting with pulling out of Washington, D.C.'s orbit.

With U.S. ships arriving on the scene so quickly, the Pentagon has been given a chance to demonstrate the value of having dozens of U.S. bases in Japan, which hosts some 50,000 military personnel.

"What we are doing here is diplomacy," said George Aguilar, the commander of the HS-4 Black Knights, a helicopter squadron on the Ronald Reagan. "This is our best friend in the region."

So far, it seems to be a highly successful effort, at least in the areas the helicopters visited. On Sunday, as the squadron ferried supplies to towns devastated by the tsunami, usually to schoolyards or sporting grounds converted into landing zones, Japanese residents welcomed them. Many were isolated when roads were washed away.

"We will always remember the Americans' coming at a time when we needed help," said Osamu Abe, 43, an official in the town of Minamisanriku, where Aguilar's squadron dropped off bottled water, military rations and children's clothing Sunday.

At the same time, the U.S. military has found itself trying to achieve a delicate balance.

The United States has played a role in many aspects of the response to the recent crisis in Japan, including sending firetrucks to the stricken Fukushima Daiichi nuclear plant. But the Americans seem keen to avoid embarrassing the Japanese, or suggesting that the U.S. is running the show.

The Americans said they wanted to stay until the Japanese were able to get regular supplies into the remote coastal towns that were slammed by the waves. Japan appeared to be making progress in building such overland links, they said.

The U.S. response to the nuclear crisis includes not only firetrucks, adding to efforts to spray water on the overheating fuel rods, but also reconnaissance aircraft, which have been helping the Japanese monitor radiation levels.

On the Ronald Reagan, emissions from the crippled plant have been an acute concern. The Navy fliers said they were trying to stay at least 50 miles away. When helicopters returned from relief, they and their crew were carefully scanned with Geiger counters.

The carrier itself also has pulled back to at least 100 miles away from the reactors. When the wind near the plant changed direction, the Ronald Reagan went into what sailors called "Circle William" mode — closing off all hatches and ventilation openings to prevent outside air from entering. Crew members said radiation was something the ship had not had to deal with in years.

"We're digging out the old Cold War-era manuals on how to protect the ship from radiation," said Aguilar, the squadron chief.

Aguilar, 40, said the damage and death toll from Japan's tsunami were far larger than another disaster in which he was involved in relief efforts: Hurricane Katrina.

"This exceeds Katrina," he said. "This looks like the arm of God just scraped the land clean."

He and other U.S. helicopter crewmen said they were stunned by the randomness of the tsunami, witnessed by a large ferryboat placed perfectly atop a three-story building, or an entire house floating intact miles out at sea, with curtains still in the window. A debris field of splintered wooden pieces of Japanese homes and capsized boats of all sizes encircled the Ronald Reagan, about 15 miles offshore.

Much of what the Americans have handed out are goods taken from their own ships: extra food and blankets, and even the sailors' own clothes.

There were stuffed toys for children, too.

To alleviate food shortages in the shelters, the Ronald Reagan sent 77,000 frozen hot dogs to a Japanese warship, which boiled them and gave them out.

Airmen in other squadrons also spoke at length about the Japanese warmth. Michael Adomeit, 34, a helicopter crew member from the destroyer USS McCampbell recalled one drop-off.

"There was this line of grandmas came out to give us hugs and say thank you," he said. "It makes you realize how important this mission is."