In the 1935 case Washington v. Oregon, the U.S. Supreme Court was tasked with resolving a dispute between two states over their shared border along the Columbia River. The state of Washington claimed that it owned all of the river up to its northern bank, while Oregon argued that both states had joint ownership of this waterway under common law principles and historical precedent. After examining various treaties, maps, and other documents dating back to when these territories were first acquired by the United States from Great Britain in 1846, as well as considering how similar disputes had been resolved in other cases involving riparian boundaries between states (such as New Jersey v Delaware), the court sided with Oregon's interpretation and ruled that each state held jurisdiction over half of this river according to an imaginary line running down its middle (the "thread" or "thalweg"). This decision has since served as a key legal precedent for determining interstate borders across bodies of water throughout America.

In the dissenting opinion for Washington v. Oregon, it was argued that the Supreme Court should not have jurisdiction over this case as it is essentially a dispute between two states about their respective water rights. The dissenting justices believed that such disputes should be resolved through negotiation and agreement between the states involved, rather than by federal intervention. They also expressed concern about the potential implications of this ruling on future interstate conflicts, suggesting that it could set a precedent for increased federal involvement in state affairs. Furthermore, they disagreed with the majority's interpretation of certain key legal principles related to water rights and interstate relations. Overall, they felt that this decision represented an unwarranted expansion of federal power at the expense of state sovereignty.