The Springbok was a case heard by the United States Supreme Court in 1866. The case involved a dispute between the owners of the Springbok, a British vessel, and the United States government. The Springbok had been seized by the United States Navy for alleged violations of the Neutrality Act of 1818. The owners of the vessel argued that the seizure was unlawful and that the vessel should be released. The Supreme Court ultimately sided with the owners of the Springbok, ruling that the seizure was unlawful. The Court held that the Neutrality Act of 1818 did not apply to the Springbok, as the vessel was not engaged in any hostile acts against the United States. The Court also held that the seizure was not authorized by any other law, and thus was unlawful. The Springbok case was significant in that it established the principle that the United States government cannot seize a vessel without proper legal authority. This principle has been applied in numerous cases since then, and is still relevant today.

In The Springbok, the Supreme Court was asked to decide whether a ship that had been sold in violation of a foreign decree could be seized by the original owner. In an 8-1 decision, the court held that it could not. Justice Field wrote for the majority and argued that while Congress has authority over foreign commerce, it cannot interfere with private contracts made between individuals in another country. He further stated that if such interference were allowed, then other countries would have similar rights when dealing with American citizens abroad. Justice Swayne dissented from this opinion and argued instead that Congress does have power to protect its citizens' property interests even when they are located outside of U.S borders; he reasoned that since these interests are connected to our nation's economy and welfare, they should be protected regardless of where they may lie geographically or legally speaking.