What does McCarthyism refer to and how did it affect American society during the Cold War?

McCarthyism is the practice of making accusations of subversion or treason without proper regard for evidence.[1] The term refers to U. S. Senator Joseph McCarthy and has its origins in the period in the United States known as the Second Red Scare, lasting roughly from 1947 to 1956 and characterized by heightened political repression as well as a campaign spreading fear of influence on American institutions and of espionage by Soviet agents.