They won in Vietnam in a way, because they were fighting against vietcong, and it eventually got defeated. The communism in vietnam that was supported by the Soviets lost, and Russian communism followed the same path.
They wanted to test their arsenal and they did. Was it worth it? I'd say no, but some military scientists would think otherwise.
If we're talking about fire power, I'd say Americans could actually win this. If we are thinking about American Vietnam war, i think that would be a fluke. I'm pretty sure they learned from this mistake because it's a huge mistake. Allies wise, America has alot of nations under their belts. Both countries that owe the US and countries that the US has dirt on. I just hope we won't have to test this theory