USA HISTORY

Detailed explanation-1: -The basic idea was that the American’s needed to prevent the first domino from falling (country turning to communism) in order to prevent the spread of communism. As such, historians now argue that the United States used the Domino Theory to justify its involvement in Korea, just as it did in the later Vietnam War.

Detailed explanation-2: -Concerned that the Soviet Union and Communist China might have encouraged this invasion, President Harry S. Truman committed United States air, ground, and naval forces to the combined United Nations forces assisting the Republic of Korea in its defense.

Detailed explanation-3: -The United States entered Vietnam with the principal purpose of preventing a communist takeover of the region. In that respect, it failed: the two Vietnams were united under a communist banner in July 1976. Neighbouring Laos and Cambodia similarly fell to communists.

Detailed explanation-4: -North Korea was communist and they invaded the capitalist country of South Korea. The United States entered the war to prevent the spread of communism. North Vietnam was communist and wanted to make North Vietnam and South Vietnam one country.