During the Vietnam War, U.S. aircraft bomb the major North Vietnamese population centers of Hanoi and Haiphong for the first time, destroying oil depots located near the two cities. The U.S. military hoped that by bombing Hanoi, the capital of North Vietnam, and Haiphong, North Vietnam's largest port, communist forces would be deprived of essential military supplies and thus the ability to wage war.
In 1961, U.S. President John F. Kennedy sent the first large force of U.S. military personnel to Vietnam to bolster the ineffectual autocratic regime of South Vietnam against communist forces. Three years later, with the South Vietnamese government crumbling, President Lyndon B. Johnson ordered limited bombing raids on North Vietnam, and Congress authorized the use of U.S. ground troops. By 1965, Vietcong and North Vietnamese offensives left President Johnson with two choices: escalate U.S. involvement or withdraw. Johnson ordered the former, and troop levels soon jumped to more than 300,000 as U.S. air forces commenced the largest bombing campaign in history.
However, as the Vietcong were able to fight with an average daily flow of only 20 tons of supplies from North Vietnam, and U.S. forces in Vietnam required 1,000 times as much, the bombing of communist industry and supply routes had little impact on the course of the war. Nevertheless, North Vietnamese leader Ho Chi Minh placed the destruction of U.S. bombers in the forefront of his war effort, and by 1969 more than 5,000 American planes had been lost. In addition, the extended length of the war, the high number of U.S. casualties, and the exposure of U.S. involvement in war crimes such as the massacre at My Lai turned many in the United States against the Vietnam War.
In 1973, representatives of the United States and North and South Vietnam signed a peace agreement in Paris, ending the U.S. military involvement in the Vietnam War. On April 30, 1975, the last few Americans still in South Vietnam were airlifted out of the country as Saigon fell to communist forces. The Vietnam War was the longest and most unpopular foreign war in U.S. history and cost 58,000 American lives. As many as two million Vietnamese soldiers and civilians were killed.