The term McCarthyism became a catchword for charging and accusing that people were not loyal to the United States without evidence.
McCarthyism refers to the practice of making accusations of subversion or treason without proof. The term ris related to U.S. senator Joseph McCarthy (R-Wisconsin) and was originated in the period in the United States called the Second Red Scare, which protracted from the late 1940s through the 1950s.