During Tet, one of my ROTC instructors was there with the 1ID, IIRC. He was an Airborne Ranger Infantry Officer. He taught us a few things about Tet. A very interesting Offensive.
From all sources, I have gotten, the US/SEATO won in the field but lost in the media. I've heard some say Walter Cronkite was a big contributor to labeling Tet a US/SEATO loss.
Again from various sources. The NVA knew they couldn't hold all they took even with the VC/NLF assistance. The figured the best they could do is hold 1 out of 10 villages seized. But as long as they inflicted losses on the US. And it was reported in the media. As it was daily. They knew/believed the US citizens would push for a withdrawal from SE Asia/Vietnam. With mounting US casualties, being shown on the TVs in US homes, etc.
The NVA pushed the VC forward anywhere the could. To attack and seize as many OBJs has they could. The NVA also knew that for every hard core Communist in the VC. There was probably a Nationalist as well. Who didn't care about being a Communist. But just wanted another foreign power out of Vietnam. Their backyards …
The NVA wanted to bleed the VC out. While causing a much damage to the US/SEATO as they could. The NVA didn't want to have to deal with Nationalists after the South Vietnam forces were defeated. And the US/SEATO was gone.
The VC were pretty much down to maybe 3 Rgt sized units mostly in the Cham Coast region. At the time of the next NVA Offensive in '72. Sometimes referred to the Year of the Rat Offensive. Based on the Asian astrological calendar..
And it was believed the remaining VC were fleshed out by some NVA. And it took until '72 for the NVA to build up enough assets to go on the offensive. After the high losses they suffered at Tet in '68.
Plus from the US side. The anti-War movement was more of an anti-draft movement. It probably wouldn't have existed or it would on a much small level. If there was no Draft. Most Americans couldn't find Vietnam on a map. Let alone care about "the peaceful famers" of the region that the US was causing a lot of damage to. As the anti-war movement liked to say etc. And it was true the US firepower was high tech and massive. But it was fighting a war of attrition against the birth rate of a SE Asian county(s)/region. Much of it 3d World. As Dan Galloway had said. The author of "We were Soldiers once and Young". Who as a journalist was with the US Cav at LZ X-ray, etc.
As time passed, US/SEATO troops would find dead NVA as young as 13 years old. And sometimes with tattoos on the NVA soldiers' arms saying, "Born in the North to die in the South". The North's leadership, Ho, Giap, etc. wanted all of Vietnam united under their Communist rule. And were willing to use up as many assets they could to make it happen.
They fought the French and they left. Now they are taking on the US/SEATO. They knew they didn't have to "win" but just not "lose". And the new invaders, would leave just like the French did eventually.