Answer:
Joseph McCarthy had a major impact by creating an atmosphere of hysteria and paranoia in the early fifties. People were scared of the Soviet Union after the atomic bomb had been set up in the USSR.
McCarthy claimed that communists were infiltrated like the Rosenbergs in many sectors of American society and thus betrayed their motherland to serve the interests of the Soviet Union. He even drafted lists that were completely unreliable.
Step-by-step explanation: