Before the Vietnam War, most Americans would have been hard pressed to locate Vietnam on a map. South Vietnamese President Diệm's regime was extremely unpopular, and war broke out between Communist North Vietnam and South Vietnam around the end of the 1950s. Kennedy's administration tried to prop up the South Vietnamese with training and assistance, but the South Vietnamese military was feeble. A month before his death, Kennedy signed a presidential directive withdrawing 1,000 American personnel, but shortly after Kennedy's assassination, new President Lyndon B. Johnson reversed course, instead opting to expand American assistance to South Vietnam.

Operation Speedy Express was a highly controversial military operation carried out by the U.S. Army supported by the Army of South Vietnam (ARVN) as well as regional and popular forces during the Vietnam War. It lasted from December 1968 until May 1969 and took place in the Mekong Delta's Kien Hoa and Vinh Binh provinces. The operation was a part of U.S. Army "pacification" efforts toward the Viet Cong, as American forces sought to interdict Viet Cong supply and communication lines from Cambodia and deny them the use of operational bases. Formally, the operation involved 8,000 U.S. soldiers and resulted in 242 American lives lost compared to 10,899 Viet Cong and People's Army of Vietnam (PAVN) killed, according to Department of Defense records. Operation Speedy Express was considered successful by U.S. standards, as determined by the primary metric of body counts. However, while the number of Vietnamese dead, including civilians, is unknown, it is assumed to surpass 5,000, and the high number of casualties was attributed to the indiscriminate use of firepower, which included air and artillery strikes in densely populated areas.