After the Tet Offensive of 1968, the Viet Cong ceased to be a fighting force on the battlefield; all the U.S. forces fought from that point on were NVA regulars. Those NVA regulars were pretty much defeated by 1973. At that point, all we had to do is facilitate Vietnam defending itself.

In 1975, the Democratic Congress cut off aid that was designed to allow South Vietnam to defend itself with American weapons. Without any American aid, Vietnam was doomed to defeat. The Soviets and CHICOMs did not cut off aid to North Vietnam. ... We set a precedent with that war that we will leave our friends twisting in the wind.