Joseph Raymond McCarthy (1908 ¡V 1957) American politician who served as a Republican U.S. Senator from the state of Wisconsin from 1947 until his death in 1957. Beginning in 1950, McCarthy became the most visible public face of a period in the United States in which Cold War tensions fuelled fears of widespread communist subversion. He is known for alleging that numerous communists and Soviet spies and sympathizers had infiltrated the United States federal government, universities, film industry, and elsewhere.