In 1908, the Supreme Court struck down Section 10 of the Erdman Act of 1898 in the notorious case of Adair v. United States.1 Section 10 made it a misdemeanor for employers in the railroad industry to blacklist members of railroad unions or to require employees to sign “yellow-dog” contracts, that is, contracts promising that the employee would not join a labor union. The Court ruled that Section 10 was unconstitutional because it interfered with the “liberty of contract” allegedly protected by the United States Constitution.