In the case of Arizona v. California et al., 1930, the Supreme Court was asked to settle a dispute between states over water rights from the Colorado River. The state of Arizona filed a suit against California and several other entities including Nevada, New Mexico, Utah and the United States itself for equitable apportionment of waters in this river system. However, before reaching any decision on water allocation among these states, it had to be determined whether or not Congress had already allocated such waters by enacting Boulder Canyon Project Act (BCPA). The court ruled that BCPA did indeed allocate waters among lower basin states which included both Arizona and California thus making it unnecessary for them to make an independent determination about division of these resources. This ruling essentially upheld Congressional authority over interstate disputes regarding natural resources like rivers.

In the dissenting opinion for Arizona v. California et al., 1930, it was argued that the Supreme Court should not have original jurisdiction over this case. The dissenting justices believed that the dispute between Arizona and California regarding water rights to the Colorado River was a political question, rather than a legal one. They contended that such issues should be resolved by Congress or through interstate compacts, not litigation in federal court. Furthermore, they expressed concern about potential conflicts of interest among justices who hailed from states involved in similar disputes over water resources. Ultimately, they disagreed with their colleagues' decision to exercise judicial power in this matter and would have dismissed Arizona's complaint on jurisdictional grounds.