The president may not issue exemptions to customary international law at discretion. Federal courts may look to customary international law because it is an integrated part of American law. Decided January 8, 1900 (argued 1899). Opinion of the Court: Horace Gray → go there Dissenting: Fuller. Topic: Foreign. The Paquete Habana; The Lola, 175 U.S. 677 (1900), was a landmark decision of the United States Supreme Court concerning the applicability and recognition of international law by the United States. The Court held that the capture of fishing vessels as prizes of war violated customary international law, which is integrated with U.S. law and binding as such. Paquete Habana influenced subsequent court decisions that incorporated international law regarding other matters. The case is also notable for citing a wide breadth of historical and international sources, including jurists from around the world and foreign state practices going back centuries. Wiki link