In the United States v. Texas case of 1895, the U.S. Supreme Court ruled in favor of Texas regarding a dispute over its boundary with Oklahoma (then known as Indian Territory). The controversy arose when Congress established Greer County in present-day Oklahoma and claimed it was not part of Texas despite earlier treaties suggesting otherwise. The federal government argued that the 1819 Adams-Onís Treaty between Spain and the U.S., which defined Louisiana's western border along the Red River, meant that all land north of this river belonged to them - including Greer County. However, Texas contended that according to their interpretation of this treaty, they owned all lands southward up to North Fork’s source – thus incorporating Greer county into their territory. The Supreme Court sided with Texas based on historical evidence showing consistent recognition by both Mexico and early American settlers about Texan jurisdiction over these disputed lands before Oklahoma became an organized territory under US law. This decision led to a significant expansion for Texas at Oklahoma's expense.

In the dissenting opinion for United States v. Texas, Justice John Marshall Harlan argued that the Supreme Court did not have jurisdiction over this case because it was a dispute between a state and the federal government, which should be resolved by Congress or through negotiation rather than litigation. He also disagreed with the majority's interpretation of international law regarding boundary disputes and believed that Texas had retained its sovereignty over disputed territory when it joined the Union. Furthermore, he contended that even if there were grounds to sue under international law, such suits could only be brought by sovereign nations against each other in an international court of justice - not in domestic courts like those of America. Finally, he expressed concern about setting a precedent where states could sue each other or their own citizens in federal court over territorial disputes.