Foreign involvement includes the USSR and China.
Of course. Both were power-hungry, murderous states too
I agree such wars are generally folly though and unlikely to have a happy ending.
What would you have done if faced with the situation that a “free” election would be rigged in the North, and the winner would likely kill hundreds of thousands of people?
(They killed tens of thousands in the North and this was where they had least opposition)
I don't know what I would have done because such a decision requires extensive intel on the situation as well as thorough consideration of all possible options. However, I do know that I almost surely wouldn't have backed a coup and deliberately fostered disruption in South Vietnam just because its leader's plans conflicted with mine, a foreign leader. That's not what someone does if their intention is to save lives and advance peace.