Final answer:
Joseph McCarthy was a senator responsible for the anti-Communist hysteria known as McCarthyism, which is characterized by baseless accusations and tactics that disregard evidence.
Step-by-step explanation:
Joseph McCarthy was a Republican senator from Wisconsin known for his role in stoking anti-Communist fears in the United States during the early 1950s. The term McCarthyism refers to the practice of making accusations of subversion or treason without proper regard for evidence. McCarthy rose to prominence by claiming to have a list of Communists within the U.S. government although he never provided any verifiable evidence to support his accusations.
McCarthy's unfounded allegations led to a period of heightened fear and political repression known as the Red Scare. He used his position as chair of the Senate Committee on Government Operations to launch a series of investigations that smeared the reputations of individuals and intensified the atmosphere of fear. His tactics included aggressive questioning, guilt by association, and attacks on dissenters, which often violated their civil liberties.
The term McCarthyism has since become synonymous with the reckless and unsubstantiated accusations that characterized this era. His downfall came when he extended his allegations to include members of the U.S. Army, leading to the famous Army-McCarthy hearings, which were televised and exposed his lack of evidence and unscrupulous methods. The Senate eventually censured McCarthy, representing a symbolic end to his influence.