In the case of State of Oklahoma v. State of Texas, 1923, the United States Supreme Court was called upon to resolve a boundary dispute between Oklahoma and Texas over an area known as Greer County. The controversy arose from differing interpretations of the Treaty with Spain in 1819 which defined U.S territories after acquiring Florida. The treaty described part of the boundary as following "the course" or "along" Red River (which separates modern-day Texas and Oklahoma), leading to ambiguity about whether it meant along its south bank or down its middle channel. In this case, both states claimed ownership over Greer County located on north side but south bank of Red River's main channel. The court ruled in favor of Texas based on historical evidence showing that both Spanish and American authorities understood at time when treaty was made that region now known as Greer county belonged to territory intended for future statehood under name 'Texas'. This decision effectively moved border between two states northward into riverbed itself by declaring all land up till southern edge is Texan territory while everything beyond belongs to Oklahoma.

In the dissenting opinion for the case of State of Oklahoma v. State of Texas, Justice McReynolds expressed his disagreement with the majority's decision to grant ownership rights over a disputed portion of land along the Red River boundary to Texas. He argued that historical evidence and past treaties clearly established this area as part of Oklahoma's territory. Furthermore, he contended that by ignoring these facts and ruling in favor of Texas, the court was not only disregarding precedent but also undermining its own credibility and authority. In addition, he criticized what he perceived as an overly literal interpretation by his colleagues on how river boundaries should be determined under international law principles - specifically their reliance on 'cut-off' theory rather than 'gradual accretion.' This approach failed to consider natural changes in river courses over time which could affect territorial boundaries between states.