McCarthyism is part of the Red Scare period of American history in the late 1940s and 1950s. During that time, Wisconsin Senator Joseph McCarthy produced a series of investigations and hearings to expose supposed communist infiltration of various areas of the U.S. government. Other aspects of the Red Scare included the House Un-American Activities Committee and the Hollywood blacklist. The term McCarthyism has since become a byname for defamation of character or reputation by indiscriminate allegations on the basis of unsubstantiated charges.