Immediately after World War II, and for the next four decades, two political ideologies -- Soviet communism and American capitalism -- vied for supremacy and influence on the global stage. During this struggle, known as the Cold War, Americans perceived communism as a viable threat to their freedom. This fear intensified into paranoia in the late 1940s and early 1950s. This so-called "Red Scare" led to compromises of civil liberties.

Communist Triumphs Abroad

In 1949, the Soviet Union successfully tested an atomic bomb, and China joined the world's communist ranks following a civil war. In 1950, North Korea's communist regime invaded pro-Western South Korea, prompting the United States and the United Nations to intervene militarily. For many Americans, these events demonstrated that the Soviet Union was planning a global communist takeover. Though the hysteria that ensued had largely subsided by the late 1950s, in the coming years, other events, some related to Fidel Castro's successful Marxist revolution in Cuba in 1959, would bring the threat of communism closer to home.

House Un-American Activities Committee

The Un-American Activities Committee of the House of Representatives, or HUAC, at once reacted to and fueled the atmosphere of the Red Scare through investigations of communist activity in the country. Among the targeted industries was Hollywood, the ranks of which HUAC believed were filled with communists. Some screenwriters and directors spent time in prison and were subsequently excommunicated from the film industry for speaking out against the committee. HUAC's investigations typically included Congressional hearings of prominent individuals. In 1948, in a famous hearing, then editor of "Time" magazine and admitted former communist Whittaker Chambers accused former State Department official Alger Hiss of being a Soviet spy. Hiss continued to deny the charges even after he was convicted for perjury.

McCarthy's Mole Hunt

In 1947, prior to the Hiss hearings, President Harry Truman had issued an executive order, known as the Loyalty Order, which established a process to screen government employees for communist sympathies. The figure most closely linked to the hunt for communists within the government, however, was Senator Joseph McCarthy from Wisconsin. In 1950, McCarthy, in a now-famous speech, announced that the State Department alone harbored more than 200 communists. A Senate investigation found no evidence that supported the senator's claim. Over the next five years, though it would prove a failure, McCarthy's mole hunt nonetheless cost upwards of 2,000 government employees their jobs.

Fear of Nuclear Annihilation

During the Cold War, the United States and the Soviet Union embarked on a competition to develop more powerful and destructive nuclear weapons. Nuclear war seemed to be on the horizon in 1962 when the United States learned that the Soviets had positioned nuclear missiles in Cuba, just 90 miles from American shores. Throughout the Cold War, Americans prepared for the possibility of a communist-provoked nuclear attack by creating fallout shelters in and around their homes meant to provide protection from radiation. School children were taught to duck under school desks in a practice akin to fire drills.