The U.S. Supreme Court case Idaho ex rel. Evans, Governor of Idaho, et al. v. Oregon et al., 1982 revolved around a dispute between the states of Oregon and Washington versus Idaho over fishing rights in the Columbia River for commercial salmon harvests which were regulated by interstate compact approved by Congress in 1977 under Pacific Northwest Coordination Act (PNCA). The PNCA was enacted to prevent depletion of fish stocks due to overfishing but did not specify how each state's share would be determined. When negotiations failed to reach an agreement on allocation percentages, Idaho sought relief from the Supreme Court claiming that its allocated share was unfairly low compared with those given to Oregon and Washington. The court ruled against Idaho stating that it had no original jurisdiction as this issue fell under congressional authority rather than judicial review since it involved interpretation and application of federal law - specifically, the PNCA - rather than resolution of a controversy among sovereign states based solely on common-law principles or equitable apportionment doctrines.

In the dissenting opinion for Idaho ex rel. Evans v. Oregon, Justice O'Connor argued that the majority's decision to uphold a lower court ruling allocating fishing rights between states was flawed because it relied on historical catch data rather than considering each state's equal right to fish in common waters. She contended that this approach unfairly favored Oregon and Washington due to their historically larger fishing industries and disadvantaged Idaho, which had less developed commercial fisheries but equally valid legal claims under interstate compact law. Furthermore, she criticized the majority for failing to consider future changes in fish populations or industry practices that could affect equitable allocation of resources among states.