Lamont v. Postmaster General, 381 U.S. 301 (1965), was a landmark First Amendment Supreme Court case, in which the ruling of the Supreme Court struck down § 305(a) of the Postal Service and Federal Employees Salary Act of 1962, a federal statute requiring the Postmaster General to detain and deliver only upon the addressee's request unsealed foreign mailings of "communist political propaganda.

4008 (1964) required the U.S. Postmaster General to detain and not deliver "communist political propaganda," unless a recipient affirmatively indicated their consent to receive such materials through the mail.

Dr. Corliss Lamont had a copy of the Peking Review detained and declined to respond to the government's inquiry as to whether he wished to receive the delivery.

The Court held:the Act, as construed and applied, is unconstitutional, since it imposes on the addressee an affirmative obligation which amounts to an unconstitutional limitation of his rights under the First Amendment.

[1]The Court was unanimous in the judgment (8–0, with Justice White recused).