The U.S. Supreme Court case, State of Montana v. State of Wyoming and State of North Dakota in 2015 revolved around a dispute over water rights between the states under the Yellowstone River Compact. Montana accused Wyoming of violating the compact by consuming more than its share amount from two tributaries to the river, primarily for irrigation purposes which was affecting Montana's own access to water resources. The court ruled in favor of Wyoming stating that it had not violated any terms as per their interpretation since there were no specific limits set on groundwater withdrawals or improved efficiency measures within the compact agreement signed back in 1950.

In the dissenting opinion for the case between Montana and Wyoming & North Dakota, it was argued that Wyoming should not be allowed to change its water use practices in a way that would decrease the amount of water available to Montana. The dissenters believed that under the Yellowstone River Compact, each state has an obligation to ensure their actions do not harm other states' ability to access their equitable share of water. They disagreed with majority's interpretation of Article V(A) of this compact which allows changes in agricultural efficiency as long as consumption remains within limits set by appropriative rights established before 1950. They contended such interpretation could lead one state consuming more than its fair share at expense of another, violating spirit and purpose behind interstate compacts like these - ensuring mutual benefits without causing undue harm. Furthermore, they expressed concern about potential negative impacts on downstream users due to upstream conservation measures or increased consumption.