It's interesting now to see that the US involvement and 'domino theory' pretext being used were actually dismantling a Catholic country; the Archbishop and President were brothers, upholding a Catholic state, and not allowing false religions a public place.
The Pentagon Papers leaked out that the entire pretext used to enter the war (being attacked in the Gulf of Tonkin) was completely, 100%, false.
Now it seems more plausible that the US was actually working to dismantle a Catholic state under the guise of dismantling Communism. I read Bella Dodd's School of Darkness recently and this is exactly the kind of work they were up to. It's a wild world out there.
Well, to his credit at least, Lyndon B Johnson strongly opposed the plan to stage the coup against Diem.
Kennedy greenlight it, though, evidently he was under the impression that a deal had been stuck to grant Diem and others safe passage out of Vietnam. He was reportedly distraught when he learned how it had ended.
General Maxwell Taylor noted that Kennedy physically blanched and left the room with "a look of shock and dismay... which I had never seen before"
So that was 11/2/1963 ... and on 11/22/1963, JFK died by the sword that he had lived by.