When the Vietnamese ambassador to the United States, Le Cong Phung, flew to Hawaii 10 days ago to confer with the commander of American forces in the Pacific, Adm. Robert Willard, he carried a succinct message: "Beware of China."

In more diplomatic language, said U.S. and Vietnamese officials, the ambassador asserted: "Vietnam and the U.S. should work together to counter China’s territorial claims and attempts to hamper free navigation in the South China Sea."

Willard, whose Pacific Command is charged with military relations with China — and deterring Chinese aggression if those relations turn sour — was said to be receptive. Willard himself could not be reached because, his staff said, he was tied up directing U.S. post-tsunami relief efforts in northeastern Japan.

The U.S. and Vietnam have been gradually forging a reconciliation that can only be called remarkable, given the long war they fought from 1954 to 1973 in which 58,000 Americans died and 1.1 million Vietnamese are estimated to have perished.

Secretary of Defense Robert Gates set the tone during a visit to Hanoi in October. "Wars end," he said at the Vietnam National University. "Nations wise enough to put past bitterness and heartbreak behind them can find in each other future friends and partners."

Ambassador Phung reflected Hanoi’s point of view and the long memories of the Vietnamese. China occupied large parts of Vietnam for a thousand years, ending in A.D. 939. More recently, China attacked Vietnam in 1979 and fought skirmishes for nearly 10 years after that.

For the U.S., China’s belligerence has been intensifying since the eruption of Chinese nationalism during the Olympics in August 2008. Beijing seems bent on driving U.S. forces and influence out of Asia. U.S. commanders have quietly but repeatedly cautioned the Chinese not to miscalculate as the U.S. intends to remain a Pacific power.

To underscore the emerging security relations between the U.S. and Vietnam, the 13th Air Force at Hickam Air Force Base here plans to deploy a "Red Horse" team of frontline engineers to Vietnam this summer to work with Vietnamese engineers on refurbishing schools and hospitals.

U.S. officials said the plan for the Air Force and other American services was to establish working relations with Vietnamese non-combat units, then move incrementally into training exercises for combat forces. Eventually, U.S. forces would like to gain access to air bases in Vietnam.

The U.S. Army Pacific at Ft. Shafter plans to bring together representatives from Vietnam and other Southeast Asian nations in a workshop on improving responses to natural disasters. The plan calls for expanding such workshops over the next two years. The Army also plans to support the medical and engineering missions of the other services.

The Navy’s Pacific Fleet at Pearl Harbor, which has sent a half-dozen warships on port calls in Vietnam in recent years, plans to hold a staff conference with Vietnamese counterparts this spring to arrange for more visits. In a breakthrough, Vietnam has announced that its port at Cam Ranh Bay has been opened to foreign navies.

For a 90,000-ton, nuclear-powered aircraft carrier to visit Cam Ranh Bay would be a vivid symbol of U.S.-Vietnam reconciliation, as the bay was the site of a huge U.S. base during the war. The port call would be intended to signal Asian nations that the U.S. seeks regional security and to remind China that the U.S. would be a formidable foe.

Last year, the aircraft from the carrier U.S.S. George Washington flew several Vietnamese military and political leaders out to the ship standing offshore. The carrier U.S.S. John Stennis did the same the year before, both actions drawing protests from Beijing, which claims sovereignty over those waters.

About the same time, the guided missile destroyer U.S.S. John S. McCain docked in Danang. The ship is named for U.S. Sen. John McCain’s grandfather, an admiral, and his father, the admiral who led the Pacific Command during the Vietnam War. Sen. McCain, a naval aviator, was shot down over Hanoi and spent six years as a prisoner of war.

A less visible but still telling sign of the gradual accommodation has been the opening of a liaison office in Hanoi by the U.S. Central Intelligence Agency.

Not every Vietnamese is keen about reconciling with the U.S., particularly older members of the Communist Party who fear the U.S. will undermine their authority. A Vietnamese official criticized a U.S. resolution on religious freedom in December, saying it failed to reflect the correct situation in Vietnam.

In the U.S., many Vietnam veterans who might be expected to be critical of reconciliation, especially those who were prisoners of war, have instead indicated that they are indifferent or supportive.

"We don’t have a lot of animosity toward the enemy," said a retired Marine who fought twice in Vietnam. "We were warriors sent by our political leaders to fight the war but then we, not the politicians, got blamed for the war. We were let down by the American public."