(1908-57) a US politician. As a Republican Senator from Wisconsin he led a campaign against Communists in US society and government in the 1950s, during the Cold War. Important and well-known people were accused of being Communists or sympathetic to Communism, often without evidence, and forced to answer questions from the Senate Permanent Investigations Subcommittee, led by McCarthy. People were also encouraged to give information about their friends and those they worked with. Many people were forced from their jobs and 'blacklisted' (= prevented from getting jobs in future). In 1954 the US Senate officially condemned McCarthy's activities and his influence decreased. Most Americans are now unhappy that the McCarthy trials were allowed to happen, and admire anyone who opposed them or refused to give evidence.