In the case of Mississippi v. Louisiana in 1955, the Supreme Court was asked to resolve a boundary dispute between the two states. The disagreement centered around an area known as West Bay, which is part of the Mississippi River Delta. Both states claimed sovereignty over this region and its resources due to shifts in the river's course over time. The court ruled that when a river serving as a boundary changes its main channel gradually through natural processes (avulsion), it does not affect state boundaries; however, if such change happens suddenly or artificially, then it may alter borders accordingly. In this particular case, they found no evidence indicating any sudden or artificial shift had occurred with respect to West Bay since Louisiana became a state in 1812; thus ruling that Louisiana held jurisdiction over disputed territory.

In the dissenting opinion for Mississippi v. Louisiana, it was argued that the Supreme Court should not have jurisdiction over this case as it pertains to a boundary dispute between two states. The dissenting justices believed that such disputes should be resolved through negotiation and agreement between the states involved, rather than by federal intervention. They contended that allowing the Supreme Court to decide on state boundaries could potentially lead to an imbalance of power in favor of the federal government at the expense of state sovereignty. Furthermore, they expressed concern about setting a precedent where any disagreement between states could be brought before and decided by federal courts, which would further undermine principles of state autonomy and self-governance.