Just as the US war in Vietnam was really about containing China's influence in Asia, so too is Washington's warm welcome this week for Vietnam's prime minister.
China's been making friends fast in its big neighborhood, and its success so far has the US and Vietnam rightly worried that Beijing's hefty diplomatic and economic body-weight might turn into real military muscle in the region.
China once occupied Vietnam for nearly a millennium, and the latest big offense to its historic adversary to the south was a quick border war in 1979, a nosebleed "lesson" to Vietnam for ousting the pro-Beijing Khmer Rouge in Cambodia.
Vietnam can't get too close to the US now for fear of another Chinese lesson, but the visit of Hanoi's prime minister does help solidify ties that have grown since the two nations opened diplomatic relations in 1995.
The visit of US warships to Vietnam since 2003 has given hope of a future alliance that will further keep US military dominance in Asia, a role that most of the region welcomes as necessary for its security and prosperity. Hanoi still needs to decide how much to welcome a US naval presence at Cam Ranh Bay and other well-known harbors of the war years.
The US, too, can't get too close to Vietnam until it moves toward free, multiparty elections and reduces human rights violations of political dissidents and religious figures. Otherwise, the Bush doctrine of promoting democracy looks hollow.
As US-Vietnam trade expands, the two nations will draw together naturally. Hanoi, despite the war, always knew it would need the US as a counterweight to other big powers. That's why, after North Vietnamese troops took over Saigon in 1975, they didn't rub it in the US nose by hoisting their flag over an empty American embassy.