The rising anxiety of Cold War and long-term anti-communism evoked atmosphere of the Second Red Scare in the United States. Patriotiots were obsessed by the idea of red infiltration; that is why they set up investigation known as the witch hunt.
Hollywood with its glamour and influence became one of the earliest major targets. During years 1947-1953 many were subpoenaed to testify before HUAC about communist infiltration in the motion picture industry.
Those who didn´t answer all questions about past political affiliations and refused to name names found themselves on the blacklist. However HUAC wasn´t only organization which participated on the blacklisting.
Soon after institutionalization of these procedures there occurred number of the ”watchdogs” for example American Legion, Motion Picture Industry Council, the motion picture companies themselves or even the Catholic Church. The Hollywood blacklist existed “only” until early 60´s but it is still one of the most controversial phenomenon.