Explanation: The strategy of "containment" is best known as a Cold War foreign policy of the United States and its allies to prevent the spread of communism after the end of World War II. As the war continued, it grew less popular. A Democratic Congress forced Nixon, a Republican, to abandon the policy in 1973 by enacting the Case–Church Amendment, which ended U.S. military involvement in Vietnam and led to successful communist invasions of South Vietnam, Laos and Cambodia. The U.S. involvement in South Vietnam stemmed from a combination of factors: France's long colonial history in French Indochina, the US War with Japan in the Pacific, and both Joseph Stalin and Mao Zedong's pledge in 1950 to support the Viet Minh's guerrilla forces.
