President Kennedy believed that if Communists toppled one regime in Asia it would produce a “domino effect,” with one country after another falling to the Communists. Kennedy, a World War II veteran, also believed that aggressive nations that attacked weaker ones threatened world peace unless they were challenged.

Kennedy’s containment efforts in Vietnam ran into difficulty because the United States did not control the situation on the ground. The U.S.-backed president of South Vietnam, Ngo Dinh Diem, had spent more than $1 billion of American aid on building up military and personal security forces to suppress political opposition rather than implement the land reform that he had promised. In 1961 Kennedy sent military advisers to help the South Vietnamese fight the Communists, but the situation deteriorated in 1963 when the Catholic Diem prohibited the country’s Buddhist majority from holding religious celebrations. In protest, Buddhist monks committed suicide by setting themselves on fire, a grisly display captured on television news programs in the United States. With political opposition mounting against Diem and with the war going poorly, the Kennedy administration endorsed a military coup to replace the Diem government with one more capable of fighting Communists. On November 1, 1963, the coup leaders removed Diem from office, assassinated the deposed president and key members of his regime, and installed a military government.

Diem’s death, however, did little to improve the worsening war against the Communists. The National Liberation Front (Vietcong), Communist political and military forces living in South Vietnam and sponsored by Ho Chi Minh, had more support in the rural countryside than did the South Vietnamese government. The rebels promised land reform and recruited local peasants opposed to the corruption and ruthlessness of the Diem regime. The Kennedy administration committed itself to supporting Diem’s successor, but by late November 1963 Kennedy seemed torn between sending more American troops and finding a way to negotiate a peace.