U.S. Marines arrive in June 1965 to protect a U.S. air base, marking the first time U.S. soldiers will fight as combat troops in Vietnam. The North Vietnamese Army and the southern Viet Cong guerrillas launch a series of vicious attacks and terrorist bombings in retaliation.
In January 1968, both the NVA and the Viet Cong launch a series of massive attacks on every major city in South Vietnam during Tet, the Vietnamese New Year. The two most important cities in South Vietnam are the scenes for some of the bloodiest fighting of the war. Though both are decisive U.S. military victories, the Tet Offensive is the biggest political crisis of Lyndon Johnson's presidency.
Having won the 1968 presidential elections, Richard Nixon decides to withdraw troops from Vietnam slowly while invading neighboring Cambodia, which many North Vietnamese soldiers use to launch attacks. By 1972, the North Vietnamese are ready to launch a full-scale attack on the south.
By 1975, the North Vietnamese are all but assured a complete victory as they overrun South Vietnam and the South Vietnamese Army falls apart. Americans struggle to evacuate the U.S. Embassy in Saigon, as the NVA is only a few miles away.