As far as Vietnam went, America had withdrawn by 1972 and the North tried a conventional attack to conquer South Vietnam. American air power broke the backs of the VC/NVA forces and the South Vietnamese repulsed the attacks.
Then came Watergate, Nixon's troubles and resignation. The Democrats in House and Senate, cut off all money, spare parts, ammunition — everything — to the South Vietnames government and denied U.S. air support so the communists could win. The 1972-1975 Democratic Congressional majorities and the MSM made certain the communists won because they had allied themselves with our enemies.
Nothing has changed — they're still the enemy and have grown stronger with their lies, deceit, and alliance with radical Islam.
Trivia: although LBJ got the blame for the war years, the guy who micromanaged the war for him was SecDef Robert S. McNamara. His policies and strategies, micromanagement including ROE and target selection, got a lot of Americans killed. After LBJ was dead, McNamara wrote a book that blamed LBJ for everything and exeronerated himself of all blame. This guy never got the credit for his despicable policies and actions.
You mean dropping bombs on vacant jungles had no positive effect? Who knew?