Shall we debate an issue 50 years stale? Alright. Had we not gone in there, the communist North Vietnamese would have taken over South Vietnam without a fight, and later on would also not have had as much of a fight taking over Laos and Cambodia. As such, communism was significantly impeded, and had we stayed for another few years the independence of South Vietnam could've been assured.
You do realize that the Communists
did take over those countries, bolstered by recruitment facilitated by U.S. bombs? In fact, do you even know which country's army put an end to the Communist regime in Cambodia?