It wasn't a win for the US military. They spent 20 years in south Vietnam, trying to keep it independent, and ultimately failed. Their stated goal was south Vietnam independence and stopping the spread of communism. Both were failed goals.

War is a continuation of politics, and here, the US lost politically (in Laos first) even if they didn't loose strategically. But let's be honest, multiple times they got their asses kicked on the field too (Unless you think logistics don't matter for an army).