They cooked the numbers deliberately to deceive the American people that we were “winning”; Tet showed that we weren’t - and the scales fell from the public’s eyes.
Millions of people died in that war, and we destabilized Cambodia in the process (leading to “The Killing Fields”). I could understand if there was a more sincere effort at the top (I believe we were right to try to help South Vietnam in the same way we helped South Korea ten years before), but it doesn’t appear there was.
We didn’t really lose Tet, Wally Cronkite said we did and he was wrong.
The shocker was... suddenly, communist sappers and infiltrators were coming out of the woodwork and according to the numbers all these Communists coming out of the woodwork should have been dead long ago but the numbers were massaged & the statistics were tortured enough that it worked and fooled the budgeteers out of more money to continue fighting the Industrialized War.
It seems to be a model which continues to this day, and of course as we all know Ike warned us of that.