this federal law, sponsored by Senator Pat McCarran (D), was enacted in response to growing domestic anti-Communist fears. ItĀ strengthened laws against espionage, limited free speech for national security reasons, and allowed for the investigation and deportation of immigrants accused of promoting Communism or engaging in subversive activities. The law isĀ also known as the Internal Security Act of 1950 or the Subversive Activities Control Act of 1950.