The Supreme Court case of State of Oklahoma v. State of Texas in 1921 revolved around a territorial dispute between the two states over the ownership and control of an area known as Greer County. The United States intervened to help resolve this conflict. The court ruled that the land in question was indeed part of Oklahoma, not Texas, based on historical treaties and agreements with Native American tribes who originally inhabited these lands before they were incorporated into U.S territory. This decision clarified jurisdictional boundaries between states, reinforcing federal authority to mediate interstate disputes under Article III Section 2 Clause 2 (original jurisdiction) of the Constitution.

In the dissenting opinion for the case of State of Oklahoma v. State of Texas, Justice McReynolds disagreed with the majority's decision to award a disputed area along the Red River boundary to Texas. He argued that historical evidence and past treaties clearly indicated that this land belonged to Oklahoma. The justice contended that previous decisions by lower courts had been ignored or misinterpreted by his colleagues in their ruling, leading them to an incorrect conclusion about ownership rights over this territory. Furthermore, he believed there was insufficient consideration given towards how such a decision would impact existing property rights within this region and potentially lead to future disputes between these states.