Communism and nuclear war: Many Americans were scared of a nuclear attack by a communist power in particular the USSR.
"Duck and cover" drills, McCarthy hunts for communists, and nuclear testing all creating anxiety over an attack that may or may not happen. Americans were willing to turn in neighbors to the government in hopes of protecting themselves from spies. After the USSR launched Sputnik, the US became very nervous about a real possibility of nuclear war with the rival super power.
