Cooley v. Board of Wardens, 53 U.S. 299 (1851), was a case in which the United States Supreme Court held that a Pennsylvania law requiring all ships entering or leaving Philadelphia to hire a local pilot did not violate the Commerce Clause of the Constitution. Those who did not comply with the law had been required to pay a fee. "[It] is of the opinion of a majority of the court that the mere grant to Congress of the power to regulate commerce, did not deprive the States of power to regulate pilots, and that although Congress had legislated on this subject, its legislation manifests an intention, with a single exception, not to regulate this subject, but to leave its regulation to the several states," wrote Justice Curtis for the majority.
