The American military did everything it was directed to do in Vietnam from the earliest days of advisers to the evacuation of the American embassy in 1975. How they were employed was decided by the politicians (specifically Lyndon Johnson/Robert McNamara from 64-68 and Richard Nixon/Henry Kissinger from 69-73, and the Democratic Congress from 74-75). LBJ/McNamara tried to fix the problem by throwing a few troops at it. They were not interested in winning the war, they just didn't want to loose it. They thought they could bring enough pressure on North Vietnam to make it agree to leave South Vietnam alone. When it didn't work they panicked and botched the war. Nixon/Kissinger wanted to force a cease-fire. Their strategy was to withdraw the American combat troops while leaving the ARVN strong enough to defend the country. This actually worked, and proved itself in 1972 during the Spring Offensive when the ARVN fought the NVA to a standstill, then--with American logistic and air support--started wiping out the NVA units trapped in South Vietnam. North Vietnam was actually FORCED to sign a cease-fire (LBJ's objective all along), which allowed the Americans to pull their troops out of Vietnam and get our POWs back. By this time Congress was dominated by ultra left liberals that wanted to see a Communist victory, not peace in Vietnam. Once Nixon was driven from power they cut off almost all aid to South Vietnam. In the meantime the USSR rearmed North Vietnam.
