American involvement in the Vietnam War lasted for two decades, through the administrations of five presidents: Eisenhower, Kennedy, Johnson, Nixon, and Ford. It was brought to an end on April 29, 1976, with Ford's order for evacuation of the American Embassy in Saigon, after the fall of the city to North Vietnam forces. Characterized as a battle against a Communist takeover of Southeast Asia, the war found support from Congress and the public through most of its first decade. But by 1966, when youth activists began questioning and protesting against the United States' involvement, they framed a ten-year debate on the underlying national political and social issues laid bare by the conflict: the unfairness and inequities of the military draft, racial discrimination, poverty, and officals deciving the public. J. Edgar Hoover, head of the FBI called the protesters "Marxists," whose aim, he said, was to destroy democracy.
As the toll of death and destruction mounted, the protest movement grew in numbers and spread across the country. Violence erupted in cities and on college campuses. Police used tear gas against protesters on the Minneapolis campus of the University of Minnesota. In Ohio, National Guard troops killed four students on the campus of Kent State University. The entire world watched in 1968 as Chicago police battled war protesters on the street outside the Democratic National Convention where, inside, Minnesota Senator Eugene McCarthy and Vice President Hubert H. Humphrey played major roles.