I followed Vietnam since 1962. Wish I’d never heard of the place.
The Peace Treaty designed by Kissinger and Nixon was part of the Vietnamization of the war. To extricate our combat troops from a war that our political leadership had no intention of winning, going all the way back to the “strategy” designed by Robert McNamara, William Bundy and John McNaughton.
Hanoi was biding their time waiting for us to quit the field. Cutting off Saigon made the process much faster for the Communists, but the defeat of South Vietnam was baked into the cake at the point when we refused to treat Hanoi like we had Berlin and Tokyo. And that decision was made in 1964.
The South Vietnamese government was never all that popular. The perception was that it gave too much power to the minority Catholic population.
The money — it was only the money. Kissinger’ s book and life do NOT bear out the “ baked in the cake” scenario. We abandoned them after incredible sacrifice because of the anti-war pro communist Democrats in congress cutting off the money. IMO