The Antelope was a case heard by the United States Supreme Court in 1825. It involved two foreign vice-consuls, one from Spain and one from Portugal, who had seized a slave ship called The Antelope. The slaves on board were taken to Georgia where they were sold at auction. A group of individuals then sued the vice-consuls for trespass and false imprisonment claiming that they did not have authority to seize the vessel or its cargo under international law. In their decision, the court held that while it could not decide questions of international law, it found that slavery was illegal under both Spanish and Portuguese laws which meant that any action taken against those aboard The Antelope would be unlawful regardless of whether such actions violated international law or not. Furthermore, since no other nation recognized slavery as legal within their borders at this time either, all persons aboard The Antelope should be considered free citizens with rights protected by US laws even if they had been enslaved elsewhere prior to being brought into US waters.

In The Antelope, the Supreme Court was tasked with determining whether a slave ship that had been seized by the United States Navy in 1820 could be forfeited to Spain and Portugal. In a 5-4 decision, the majority opinion held that it could not because of its prior capture by an American vessel. However, Justice Story wrote a dissenting opinion arguing that since slavery was illegal under both Spanish and Portuguese law at the time of seizure, any slaves on board should have been freed regardless of their nationality or origin. He further argued that if they were indeed free persons then there would be no legal basis for forfeiture as they did not belong to either nation's government or citizens. Furthermore, he noted that even if some form of compensation were due to Spain and Portugal for their losses from this incident it should come from those responsible for capturing them rather than from innocent third parties who may have purchased them after their release into U.S waters without knowledge of their status as slaves.