Gulf of Tonkin Resolution: This was an agreement in the U.S Congress in response to two naval incidents in Southeast Asia. It gave President Lyndon B. Johnson authorization, without a formal declaration of war by Congress, for the use of conventional military force in Southeast Asia.
Tet Offensive: A major campaign of attacks launched throughout South Vietnam by North Vietnamese forces and Viet Cong in 1968; although it resulted in heavy losses for North Vietnamese forces, it significantly undermined U.S public support for American involvement in the war.
Vietnamization: This was President Richard Nixon's policy aimed at ending U.S involvement in the Vietnam War by transferring all military responsibilities to South Vietnam.