United States v. Hathaway was a United States Supreme Court case that dealt with the issue of whether a federal court had jurisdiction to try a case involving a crime committed on a ship in international waters. The case involved a man named Hathaway, who was accused of murdering a sailor on a ship in the Caribbean Sea. The United States argued that the federal court had jurisdiction to try the case, as the crime was committed on a ship that was registered in the United States. The Supreme Court agreed with the United States, ruling that the federal court had jurisdiction to try the case. The Court reasoned that the crime was committed on a ship that was registered in the United States, and thus the federal court had jurisdiction to try the case. The Court also noted that the crime was committed in international waters, and thus the federal court had jurisdiction to try the case. The Court's ruling established that the federal court had jurisdiction to try cases involving crimes committed on ships registered in the United States, even if the crime was committed in international waters.

In United States v. Hathaway, the Supreme Court was tasked with determining whether a defendant could be convicted of an offense that had been committed prior to the passage of a law making it illegal. The majority opinion held that Congress did have the power to make such retroactive laws and thus affirmed Hathaway's conviction. However, Justice Field dissented from this decision on two grounds: firstly, he argued that Congress does not possess any inherent authority to pass ex post facto laws; secondly, he maintained that even if they do possess such authority in certain circumstances, those circumstances were not present in this case as there was no emergency or other pressing need for immediate action by Congress when it passed its legislation criminalizing Hathaway's actions. Ultimately then, Field concluded that convicting someone under these conditions would violate both due process and equal protection rights guaranteed by the Constitution and should therefore be overturned.