The document discusses Joseph McCarthy and McCarthyism in the United States during the 1940s and 1950s. It describes how McCarthy, a U.S. Senator, led an aggressive campaign claiming that Communist spies had infiltrated the United States government without providing evidence. This led to widespread fear and suspicion of Communist infiltration and caused thousands of Americans to lose their jobs. Hollywood screenwriters and directors were also targeted during this period known as the Red Scare.