Communism, an ideology rooted in the theories of French utopian socialists, was molded by theorist Karl Marx into a political doctrine espousing a classless social structure and policies that benefit the community as a whole. By the 1950s, the Communist Party under Joseph Stalin controlled the Soviet Union and the Eastern Bloc nations. Communism had also spread to North Korea and China. The United States, concerned with communism's geopolitical effects, was compelled to establish a foreign policy calling for containment of communism and a domestic policy that called for rooting out communist sympathizers.

Building the Bloc

Following World War II, the Soviet Union exerted military and political control over Eastern Europe, which it had liberated from Nazi rule. The Soviet Union viewed its Eastern European ally nations as a buffer zone between outside military threats and the Soviet eastern border. These countries also would serve, Soviets communists surmised, as an additional layer of protection from Western influences and competing ideologies. In 1955, the Soviet Union strengthened the alliance among these nations by establishing the Warsaw Pact. The Soviet communists controlled the pact and used it to suppress dissent in Hungary in 1956.

The Wall of Shame

One of the most profound effects of communism in the 1950s was the defection of thousands of citizens from communist-controlled East Berlin to democratic West Berlin. It is estimated that about 3.5 million people fled communist Eastern Bloc countries via East Berlin prior to the construction in 1961 of the Berlin Wall. Communist officials in East Berlin insisted the wall, which they referred to as "The Anti-Fascist Protection Rampart," was not constructed to imprison its citizens, but to protect them from West Germans, whom they claimed had not been fully "de-Nazified".

Keeping Back North Korea

In the summer of 1950, communist North Korea invaded democratic South Korea, triggering a police action response by United Nations member countries. The U.S. viewed the invasion as a communist military challenge to freedom worldwide. The conflict intensified in November of 1950 when communist China lent its support to North Korea. A major commitment of U.S. air and naval forces was required to drive communist forces back to the post-World War II temporary border between the two Koreas. After several years of war, a 1953 armistice made the division permanent and established a nearly 2 1/2-mile wide demilitarized zone between the two countries.

Communists Around Every Corner

In the 1950s, Americans witnessed the creeping of communist ideologies into the far corners of the world. Americans grew fearful that communism also was spreading undetected within the nation's borders. This mindset of fear, known as the Red Scare, led to government actions that had a far-reaching and debilitating effect on the American public, and included the persecution of thousands of suspected communist sympathizers. Everyone from government officials to entertainment industry figures could be subject to suspicion, or worse, called to testify before the House Un-American Activities Committee. Although Senator Joseph R. McCarthy is notoriously remembered as the leader of the 1950s communist "witch hunts," FBI Director J. Edgar Hoover also was quick to accuse many liberal political leaders, such as Martin Luther King Jr., of being subversives.