In the 1970 case Ely v. Klahr, the U.S. Supreme Court addressed a challenge to Arizona's legislative apportionment scheme following the 1960 census. The plaintiffs argued that this scheme violated their Fourteenth Amendment rights by diluting their votes in comparison with other voters across districts due to unequal population distribution among these districts. The District Court upheld most of Arizona’s plan but ordered some adjustments for certain counties and directed that at-large elections be held until new district lines were drawn up after the next census. The Supreme Court reversed this decision, holding that it was not enough to simply wait for future censuses and redistricting plans to correct existing constitutional violations regarding voter equality; immediate action was required when such violations were identified. Furthermore, they ruled against using at-large voting as a remedy because it could potentially further infringe upon minority representation rather than ensuring equal protection under law.

In the dissenting opinion for Ely v. Klahr, Justice Hugo Black argued that the majority's decision to uphold Arizona's redistricting plan was inconsistent with previous Supreme Court rulings on equal representation. He contended that by allowing a state to use population data from an outdated census, rather than more recent estimates, the court was effectively sanctioning unequal representation in violation of the "one person, one vote" principle established in Reynolds v. Sims (1964). Furthermore, he criticized the majority for approving a temporary plan which allowed some districts to have significantly more residents than others based on arbitrary geographical boundaries and political considerations. In his view, this approach undermined democratic principles and failed to ensure fair and effective representation for all citizens.