"What Happened in Vietnam?"
In narrow military terms, the US had the capacity in 1972 to prevent South Vietnamese collapse, and in some sense the South Vietnamese position was stronger than it had been during parts of the 1960s. But these facts are almost irrelevant to the conclusion of the war; the North Vietnamese weren’t going to give up, and knew that they could force the US to pay a higher price than it was willing to by continuing the fighting. Everyone on all sides of the conflict understood these basic points, and only someone who utterly refuses to acknowledge the political dimension of military conflict could misunderstand the situation as badly as Rodman.
I concur. I should add that I was taught this material by Stephen Peter Rosen who’s something of a frothing right-winger. US military support for the Saigon regime had a fundamentally paradoxical quality to it. South Vietnamese forces had access to better equipment and training than did North Vietnamese forces, but they performed much worse than the North Vietnamese because their government lacked legitimacy. It lacked legitimacy because it was seen as a kind of corrupt quisling regime, a creature of French and then American imperialism. Massive external military support staved off military defeat, but made it completely impossible for Saigon to constitute itself as a politically legitimate alternative to unification under a nationalist regime in Hanoi.