I was raised in an old-fashioned American tradition and there were certain homely things that were taught to me: To try to tell the truth, not to bear false witness, not to harm my neighbor, to be loyal to my country, and so on. In general, I respected these ideals of Christian honor and did as well with them as I knew how. It is my belief that you will agree with these simple rules of human decency and will not expect me to violate the good American tradition from which they spring.

Lillian Hellman (1905-1984) American playwright, screenwriter

Letter to Rep. John S. Wood, House Committee on Un-American Activities (19 May 1952)
    (Source)

On declining to "name names" before HUAC (see here). National Archives copy. Reprinted in The Nation (31 May 1952).

As a result of the letter and her invoking the Fifth Amendment at the HUAC hearings, Hellman was put on the Hollywood Blacklist for the rest of the decade.