After three trial voyages, the humanitarian missions of the U.S. Navy's hospital ship Mercy and other vessels have become fixtures in America's security posture in Asia and the Pacific.

Mercy has just returned to its home port in San Diego after a five-month expedition to the Philippines, Vietnam, Timor Leste, Papua New Guinea and Micronesia. Doctors aboard the ship treated 90,693 patients, of which 1,370 required surgery and 14,866 had dental care. Veterinarians treated 6,655 animals, vital to livelihood in many developing countries.

In one operation, Cmdr. Kenneth Kubis, a Navy eye surgeon, and Capt. Tighe Richardson of the Air Force removed cataracts that had nearly blinded a 12-year-old Filipina, Marylin Kansi, when she was 4. A day after surgery, she could see shapes and colors and, Kubis said, "she could reach out and grab the nose of her new stuffed animal."

Seabees from Naval Construction Battalions flew in to undertake 26 projects such as a wastewater treatment plant in the Philippines and a community center in Papua New Guinea. Last year, the amphibious ship Peleliu was temporary refitted as a hospital ship for a similar passage. The year before, Mercy initiated the humanitarian journeys. Another amphibious ship will go next year, senior officers said.

The crews have included medics from Australia, Canada, Chile, Japan, South Korea and New Zealand. More came from civilian organizations such as Operation Smile, which repairs cleft palates, a common ailment in Southeast Asia. Doctors and nurses from Vietnam, a former enemy, and China, a potential adversary, came aboard to join the medical effort.

Secretary of Defense Robert Gates put the Mercy missions into context even though he did not mention them in a speech to the National Defense University in Washington last week. In campaigning against terror, he said, "We cannot kill or capture our way to victory."

Instead, Gates asserted, the U.S. should "promote better governance, economic programs to spur development, and efforts to address the grievances among the discontented from which the terrorists recruit. It will take the patient accumulation of quiet successes over a long time to discredit and defeat extremist movements."

Some U.S. military officers and defense specialists contend that the armed forces are intended to win the nation's wars, and this humanitarian effort should be assigned to the State Department and other civilian agencies. Gates partly agreed that "it is not a soldier's job" but added that "sometimes, only a soldier can do it."

Gates, as he has several times recently, said the U.S. needs better strategic communications in which actions often are more telling that words. It seems Mercy's missions are just such actions.

Capt. William Kearns, the naval officer who commanded Mercy's voyage, said: "We have to be flexible. We have a great hospital ship, why not use it?" Moreover, he said, "Our doctors got to learn about tropical diseases they might not have seen before."

Kearns, in an interview at Pearl Harbor, said: "I think we've got this down to the right approach and tone." A key move, he said, was getting things lined up before the ship sailed. "We did a site survey about four months in advance of the ship's arrival to discuss medical issues, engineering planning for the Seabees, and practical issues like where the ship would anchor."

"In the Philippines, we met with everyone from the undersecretary of health, Alex Padilla, all the way down to a midwife in a one-room clinic." The idea was to establish contacts and preclude opposition from local doctors who might see the foreigners as competitors.

Kearns said: "A second advance team went in 30 days before the arrival to set up logistics, arrange ground transportation, purchase materials and determine what medical equipment needed to be repaired." Another key point, he said: "Those who planned the mission were responsible for executing it."

In Vietnam, where Americans might still be suspect even though the war there ended 35 years ago, Kearns suggested they were wary. "We did preparatory work with the government that led to carefully defined work," he said. But during the 10 days the ship was in Nha Trang, he said, "we were able to expand on the agreed scope of work."

The trip had lighter moments. On a Micronesian island, a local leader said a helicopter, which many of his people had never seen, would arrive shortly. Although not planned, the U.S. team arranged for a flight to land 30 minutes later, to the applause of the islanders.

"Helicopter diplomacy," Kearns said.

Richard Halloran is a Honolulu-based journalist and former New York Times correspondent in Asia. His column appears weekly in Sunday's Focus section.