The proof lay in the 1972 Easter Offensive. This was the biggest offensive push of the war, greater in magnitude than either the 1968 Tet offensive or the final assault of 1975. The US provided massive air and naval support and there were inevitable failures on the part of some ARVN units, but all in all, the South Vietnamese fought well. Then, having blunted the communist thrust, they recaptured territory that had been lost to Hanoi. Finally, so effective was the eleven-day "Christmas bombing" campaign (LINEBACKER II) later that year that the British counterinsurgency expert, Sir Robert Thompson exclaimed, "you had won the war. It was over."
Three years later, despite the heroic performance of some ARVN units, South Vietnam collapsed against a much weaker, cobbled-together NVA offensive. What happened to cause this reversal?
First, the Nixon administration, in its rush to extricate the country from Vietnam, forced South Vietnam to accept a cease fire that permitted NVA forces to remain in South Vietnam. Then in an act that still shames the United States to this day, Congress cut off military and economic assistance to South Vietnam. Finally, President Nixon resigned over Watergate and his successor, constrained by congressional action, defaulted on promises to respond with force to North Vietnamese violations of the peace terms. Mr. Sorley describes in detail the logistical and operational consequences for the ARVN of our having starved them of promised support for three years.