Senator Joseph McCarthy was a U.S. politician from Wisconsin who served in the Senate from 1947 to 1957. He is best known for his role in the anti-communist movement during the early years of the Cold War, where he claimed that numerous communists had infiltrated the U.S. government and other institutions. His aggressive investigations and hearings led to a period known as McCarthyism, characterized by heightened political repression and a culture of fear. McCarthy's tactics included making unsubstantiated accusations and conducting public hearings that often disregarded due process. His influence peaked in the early 1950s, but by the mid-1950s, his methods faced increasing criticism. Ultimately, he was censured by the Senate in 1954, and his political career declined rapidly thereafter.