Total BS. North Vietnam was a Soviet puppet-state, intent on absorbing South Vietnam, which, arguably was a puppet-state of the US.
North Vietnam was much less a puppet of the USSR than South Vietnam was a puppet of the US. The North Vietnamese ran the war much the way they wanted, whereas the ARVN was totally dependent upon US support/guidance and would have swiftly collapsed without those (which is indeed what happened soon after the US left).
Unfortunately, our military was led by a prima donna and was more interested in PR and faking boddy counts, than in actually destroying the enemy.
Don't forget that your puppet ruler of South Vietnam, Ngo Dinh Diem, became hugely unpopular in his own half of the country, blatantly rigged the 1955 referendum and the 1959 elections, had over 100,000 suspected communists and anti-corruption whistleblowers imprisoned and killed, and was up to all other sorts of nefarious things:http://en.wikipedia....i/Ngo_Dinh_Diem
Ho Chi Minh was always far more popular among his own people, whereas Diem became such an embarrassment that the CIA supported a coup to depose him.
You are trying to sell the idea of having the US help people, who, in the end, will hate the US, anyway. I see that idea as irrational.
True, by now it might well be too late to earn the love of Syria's people, or to prevent anti-US extremists from taking over the country, or at least exerting a considerable amount of influence in post-Assad Syria. But if the US had acted decisively last year to support the rebellion/depose Al-Assad instead of wringing its hands and mouthing useless platitudes like the Arab League, a lot of Syrians might well be US supporters today.