In the 1943 case Kansas v. Missouri, the Supreme Court of the United States was asked to resolve a dispute between two states over their shared boundary line along the Missouri River. The disagreement arose due to changes in the river's course caused by flooding and avulsion (a rapid change in a river's channel). Kansas claimed that despite these shifts, it retained its original territory up to where the old riverbed had been before any alterations occurred. On contrary, Missouri argued that state boundaries should follow current watercourses regardless of how they came about. The Supreme Court sided with Kansas' argument for maintaining historical borders rather than adjusting them according to natural events like floods or avulsions. It held that when such sudden changes occur, they do not affect established jurisdictional lines unless explicitly agreed upon by both parties involved. This decision set an important precedent regarding interstate disputes related to geographical and environmental changes affecting borderlines; emphasizing on stability and respect for historical territorial limits over fluidity induced by natural phenomena.

In the dissenting opinion for Kansas v. Missouri, Justice Frank Murphy argued that the Court's decision to award damages based on a theory of unjust enrichment was inappropriate and unprecedented in interstate water disputes. He contended that such an approach failed to consider whether there had been actual harm or injury caused by Missouri's actions, which he believed should be a prerequisite for any damage award. Furthermore, he expressed concern about the potential implications of this ruling on future cases involving similar issues between states. In his view, it could lead to unnecessary litigation and conflict as states seek compensation not based on tangible harms but rather perceived unfair advantages gained by their neighbors' use of shared resources.