Final answer:
Senator Joseph McCarthy used the fear of Communist infiltration to gain political power in the 1950s. His tactics ruined people's careers and reputations, creating an atmosphere of fear and suspicion. Option 4
Step-by-step explanation:
The fear of Communist infiltration was the fear that Senator Joseph McCarthy used to gain political power in the 1950s. He made unsupported accusations of Communists taking over the government, without providing any evidence. McCarthy's tactics affected people's lives by ruining their careers and reputations, resulting in a widespread atmosphere of fear and suspicion.
There were individuals who challenged McCarthy and his tactics. Journalist Edward Murrow used his program to investigate the unfair treatment of those accused, while playwright Arthur Miller wrote a drama that drew parallels between McCarthyism and the Salem Witch Trials. Option 4