The VC isn't the problem. They eat the big one, for the most part, in Tet in 1968.
Its the NVA. And no matter how times you curbstomp them, they will keep coming until the US gets tired of the game and goes home. We beat the hell out of the NVA in the Easter Offensive in '72, and by '75, with Soviet and PRC help, they were back to play another round.
The fat is, Vietnam was not the center of gravity of the Cold War - that was Germany - and we were not going to 'pay any price, and bear any burden'. Sooner or later, the NVA wins... and it doesn't do the Soviets a bit of good fifteen years later.
Unless of course in my opinion the United States invades North Vietnam and militarily occupies it.
But Mung, that's not a surge. That's an invasion. And those are two different things.
Sure: you could send more troops into South Vietnam. It's always possible. The troops were there. EUCOM never gave troops out to PACCOM through the 50s, 60s, or 70s.
EUCOM never gave troops out, in fact, until Desert Storm. Then, because the Wall had fallen and Communism had drank the Kool-Aid, NATO felt sure of itself and could afford to let European Command give troops out to CENTCOM (in the form of VII Corps) for the offensive into Kuwait and Iraq.
If America were to be reverse the convention of the time and
take regular troops from EUCOM, then they could certainly get the manpower. But when Nixon put Vietnamization into place, that also affected which troops (on a man-to-man basis) could be rotated to Vietnam.
Once you were rotated out of Vietnam after the beginning of Vietnamization, you couldn't go back. So any troops sent to Vietnam in a surge pattern would have to be from units that had never gone before, and filled with folks who hadn't been to Vietnam in their last tour.
Believe me, man: I spent a good 3 pages on a whole other thread hashing this out. And that thread was about an honest to god incursion into North Vietnam through the DMZ.