The term "Red Scare" is commonly used to describe the feelings of fear (occasionally bordering on hysteria) that pervaded the citizens of the United States at the height of the Cold War. During the late 1940s several sensational news events took hood of the public eye, including the trial of Ethel and Julius Rosenberg for treason (which resulted in their heavily publicized executions); the acquisition of an atomic bomb by the Soviet Union and the end of the United States' monopoly on nuclear weapons technology; and the beginnings of the Korean War. Events such as these had a noticeable effect on the opinions of Americans in general about their own safety and security, and they gave rise to a subtle feeling of paranoia that centered upon a supposedly inevitable nuclear war with the Soviet Union, and the idea that evil "Communistss" were constantly working to bring the downfall of the American people.
The Red Scare hysteria manifested itself in several ways, notably through the actions of the House Un-American Activities Committee, the rise of Senator Joseph McCarthy, and the acceleration of the arms race. It also had subtle affects on America's way of life, contributing to the popularization of fallout shelters in home construction. It can also be seen as one factor that contributed to the rise and popularity of science fiction films during the 1950s and beyond. Many thrillers and science fiction movies of the period used a theme of a sinister, inhuman enemy that was planning to infiltrate society and destroy the American way of life. (One of the best examples of this is the classic film Invasion of the Body Snatchers.)