 During the fall of 1967 , the question of whether the U.S. strategy of attrition was working in South Vietnam weighed heavily on the minds of the American public and the administration of President Lyndon B. Johnson . General William C. Westmoreland , the commander of the Military Assistance Command , Vietnam ( MACV ) believed that if a " crossover point " could be reached by which the number of communist troops killed or captured during military operations exceeded those recruited or replaced , the Americans would win the war . There was a discrepancy , however , between MACV and the Central Intelligence Agency 's ( CIA ) order of battle estimates concerning the strength of Viet Cong guerrilla forces within South Vietnam . In September , members of the MACV intelligence services and the CIA met to prepare a Special National Intelligence Estimate that would be used by the administration as a gauge of U.S. success in the conflict . 
