re: Vietnam
After 1974, as I posted in another thread, Marxist regimes advanced in Angola, Mozambique, Guinea, Ethiopia, South Yemen, South Vietnam, Cambodia, Laos, Rhodesia, Afghanistan, and Nicaragua.
If we had not had eight years of solid opposition to Soviet expansionism, I have no doubt the U.S.S.R. would still be up and running today, and their client nations, like Vietnam, would not have drifted slowly off on their own courses.
It's comforting to believe that if we abandon Iraq, and inevitably after that, Afghanistan, they will just settle down and eventually turn into quiet, inward-looking nations.
I do not believe that there is a Vietnamese cultural equivalent of "jihad."