Cold War: The geopolitical tension between the United States and Soviet Union from 1947 to 1991 characterized by political hostility, military buildup, and ideological conflicts.
Joseph McCarthy: The Republican senator from Wisconsin who became infamous for his aggressive pursuit of alleged communists in government and other sectors during the early 1950s.
Loyalty oaths: Pledges required by some organizations or institutions where individuals had to declare their allegiance to the United States and disavow communism.