Final answer:
Senator Joseph McCarthy led the 1950s hunt for Communists in the United States, using unsubstantiated accusations in what became known as McCarthyism.
Step-by-step explanation:
The 1950s hunt for Communists in the United States, which became notoriety known as McCarthyism, was led by Senator Joseph McCarthy. His series of unsupported allegations claimed that Communists infiltrated the U.S. government, particularly the State Department. McCarthy capitalized on fears of Soviet espionage and used his position as chair of the Senate Committee on Government Operations to investigate and accuse individuals of disloyalty, despite a lack of evidence. Prominent political figures of the time, including Senator Robert Taft and Congressman Richard M. Nixon, initially supported McCarthy's anti-Communist crusade because it targeted Democratic politicians. However, McCarthy's tactics were eventually challenged, and he was discredited, symbolizing one of the most infamous chapters of the Cold War era in American history