We should have stayed out of it and offered only training and equipment. A land war in Asia is insanity. You only win with nukes to equal out the numerical imbalance.
Had Kennedy not screwed up the Bay of Pigs and got beat about the head like an addled school boy by Khrushchev at the 61 summit he could have politically let Vietnam make it’s own choices and saved the lives of 58K Americans in an utterly stupid war that wasn’t fought with a thought of victory, just managing the next problem or crisis.
He didn’t screw up the Bay of Pigs. He told the CIA clearly in advance that there would be no American forces. The joint chiefs and CIA simply thought they could force his hand and make it impossible to say no.
The era of the CIA setting national policy apparently still continues.