In the United States v. Kid and Watson, two men were charged with piracy for their actions in a Spanish vessel on the high seas. The Supreme Court held that although they had committed acts of violence against the crew of the Spanish vessel, they could not be convicted as pirates because there was no proof that they intended to commit robbery or plunder from any other nation. Furthermore, since Spain did not have jurisdiction over them at sea due to its neutrality during this time period, it could not prosecute them either. Ultimately, Kid and Watson were acquitted of all charges due to lack of evidence proving their intent to commit piracy under international law.

In The United States v. Kid and Watson, the Supreme Court was asked to decide whether a state court had jurisdiction over an offense committed on board of a vessel belonging to the United States. Chief Justice Marshall delivered the opinion of the Court in which he held that it did not have such jurisdiction. He reasoned that since Congress has exclusive authority over matters concerning vessels owned by or employed in service for the United States, any criminal proceedings involving those vessels must be conducted under federal law rather than state law. Furthermore, Marshall argued that if states were allowed to exercise their own laws with respect to these vessels then this would lead to confusion and conflict between different jurisdictions as well as interference with national sovereignty. As such, he concluded that only federal courts could try offenses committed on board of U.S.-owned ships and dismissed Kid and Watson's appeal accordingly