Original: The term has its origins in the period in the United States known as the Second Red Scare , lasting roughly from the late 1940s to the late 1950s and characterized by heightened fears of communist influence on American institutions and espionage by Soviet agents .
Simplified: McCarthyism is the term describing a period of intense anti-Communist suspicion in the United States that lasted roughly from the late 1940s to the mid to late 1950s .