In upholding a state statute regulating navigation standards for ships, the Supreme Court formulated the doctrine of selective exclusiveness, allowing states to regulate aspects of interstate commerce in the absence of federal laws.
A Pennsylvania law required each ship entering or leaving Philadelphia to hire a local pilot for navigation purposes. When Aaron Cooley was fined for disobeying the law, he argued that it was an unconstitutional regulation of interstate commerce. By a 6-2 vote, the Supreme Court rejected his argument. Speaking for the majority, Justice Benjamin R. Curtis
Commerce, regulation of
Pennsylvania v. Wheeling and Belmont Bridge Co.