Question

Which of the following is the best evidence that Cold War fears affected American civil liberties during the 1950s?
the Soviet explosion of an atomic bomb
the election of Dwight Eisenhower
the arrest of Soviet spies
the McCarthy Senate hearings

Answer 1

the McCarthy Senate hearings

Those hearings (and McCarthyism) led to investigations, blacklists, loyalty oaths, and ruined reputations often with little or no evidence — a direct example of Cold War fear curbing civil liberties.