In the 1983 case of Louisiana v. Mississippi et al., the Supreme Court was asked to resolve a boundary dispute between the states of Louisiana and Mississippi. The conflict arose over which state had jurisdiction over an area known as West Harbor, located in the Mississippi River near Natchez, MS. Both states claimed sovereignty based on different interpretations of historical treaties and maps. After considering both sides' arguments, including expert testimony about river movements and geographical changes over time, the court ruled in favor of Mississippi by a vote of 6-2 (with one justice not participating). The majority opinion held that despite shifts in the river's course since colonial times, West Harbor remained within Mississippi's boundaries under terms established by Congress when it admitted both states into Union.

In the dissenting opinion for Louisiana v. Mississippi et al., Justice Stevens argued that the majority's decision to deny Louisiana's motion for leave to file a bill of complaint was incorrect. He believed that there were unresolved issues regarding whether certain lands and waters belonged to Louisiana or Mississippi, which should be addressed by the court. Furthermore, he disagreed with the majority’s reliance on past cases as precedent because they did not directly address this particular dispute over territorial boundaries in light of new evidence provided by modern technology and scientific methods. Therefore, according to Justice Stevens, these disputes warranted further examination rather than outright dismissal based on outdated precedents.