In the United States v. Gilliat case of 1896, the Supreme Court ruled on a matter involving customs duties. The defendant, Gilliat, had imported goods from Canada into Vermont and was charged with paying import duties under U.S law. However, he argued that because his goods were in transit to another country (in this case England), they should not be subject to these charges as per international law principles regarding goods in transit. The court disagreed with Gilliat's argument stating that once the merchandise entered U.S territory it became subject to local laws including those related to customs duties regardless of its final destination or whether it remained unopened during its time within U.S borders.

In the dissenting opinion for United States v. Gilliat, Justice Harlan argued that the majority's decision to uphold a tax on foreign-built yachts violated principles of international law and comity among nations. He contended that such a tax was discriminatory against foreigners and thus inconsistent with America's obligations as part of an international community. Furthermore, he believed it was unconstitutional because it interfered with Congress' exclusive power over commerce regulation. In his view, states should not have authority to impose taxes or duties on imports or exports without congressional approval; doing so could lead to conflicts between different states or between individual states and foreign countries. This case represented one instance where state action had potential implications for national policy in areas constitutionally reserved for federal control.