August 2, 1964 (on Jiachen June 25), the escalation of the war in Vietnam. President Kennedy was assassinated in November

1963 by Vice President Johnson took over as required by the Constitution. This makes the United States has changed the attitude of the Vietnam War. Johnson for the escalation of the war, to prepare contingency plans for a secret, August 2, 1964, when two U.S. destroyers in the Gulf of Tonkin by North Vietnamese warships shelling, he had an excuse for the implementation of contingency plans. The U.S. Senate also gives him powers to any requirement to defend its freedom and resist armed attack help. Therefore, a large number of American soldiers were sent to Vietnam. (TodayinHistory.cn)
in 1965, the U.S. began bombing North Vietnam. In March, the ground combat forces of the United States Marine Corps landing, the end of South Vietnam more than 150,000 U.S. troops in 1969, the number of U.S. troops has been increased to 150 million. Vietcong aircraft, tanks and artillery, but rely on flexible guerrilla tactics Month January to pin down with well-equipped U.S. military. The Vietcong no uniforms, you can not distinguish between homeless villagers with Vietnam so happened like the My Lai massacre purpose is to prevent South Vietnam and other Southeast Asian countries from falling into the hands of the "Communist Party".