Domino Theory – belief that if one country fell to communism, others would follow; making the case for the U.S. to contain communism.
Korean War (1951-1953) –divided after World War II into North Korea, occupied by Soviet troops, and South Korea, occupied by U.S. forces. In 1950, following the withdrawal of the Soviet and U.S. troops, communist North Korea, supported by the People's Republic of China (PRC) with aid from the Soviet Union, and invaded South Korea, supported by the United Nations. In the U.S., some thought the United States should not be involved in the war and others felt that the United States should intervene to end the conflict and to end the expansion of communism. Many in the U.S. felt that this was part of the containment policy to stop the spread of communism. *
The result created more friction between the U.S. and the U.S.S.R. with many in the U.S. believing that the domino effect would result.
The Korean War resulted in dividing North Korea and South Korea at the 38th parallel; North Korea remained communist and South Korea gained sovereignty.