Well the US would have never won the Vietnam war because they thought they could win it by throwing money at it... Nuking Vietnam, Korea or anything else would acheive little, the Vietnam war(technically the vietnam conflict not a war as a declaration of war was never signed) was wrong, it was just another example of American neo-colonialism and imperialism. America did not just fight in Vietnam to "stop the commies" but also because of financial interests.
Vietnam was wrong because they were fighting a peasant people who had struggled against oppression for the last thousand years. The vietnamese were not allied with the soviets, they had links with communist China.
American soldiers massacred, raped and destroyed peasant's homes. Many of the soldiers were conscripted, a lot did not want to be there on the other side of the world, fighting a war against a peasant people.
How can you say that America would have won the vietnam war conventionally??? lets see...
Conscripted American vs Battle Hardened VietCong
The vietcong already overthrew the French colonialists.
The Vietnam war was not a war of weapons, it was a war of minds. America wanted to win this war of minds with guns...