The Tet Offensive failed tactically but strategically it was a great success for the North Vietnamese.
From that point on, the North relied almost exclusively on regular North Vietnamese forces because most of the Viet Cong infrastructure in the south was wiped out.

Strategically, the Tet Offensive led to the decision by LBJ to not seek another term, it was a turning point in American public opinion, and although we won the battle, we literally lost the war.

I’m just tweaking the rightwing Tet revisionists homie.