Question

Why did President Truman call the McCarran Act "a mockery of the Bill of Rights

Answer 1

On September 22, 1950 President Truman expressed in a letter to the house of representatives his concern that the McCarran Act is "a mockery of the bill of rights" as it would seriously damage the intelligence operations and security in which several departments such as CIA, Department of Defense, and Department of State are responsible. 

Answer 2

Answer:

Internal Security Act, better known as the McCarran Act, was an act passed by Congress in September 1950, prohibiting the registration of communist organizations.

According to this law, people who supported communism could not work in factories whose production was considered important for the defense of the country. Supporters of communism, or those who belonged to organizations supporting communism, could not cross the US border.

It also stated that, in the event of a state of emergency, it was possible to establish concentration camps for communists.

President Harry Truman vetoed this bill on September 22, 1950. He sent a long message to the Congress in which he criticized several aspects of the bill, calling it "the greatest danger to freedom of expression, of the press and of assembly since the Alien and Sedition Laws of 1798", a "mockery of the Bill of Rights" and a "great step towards totalitarianism".