The U.S. Supreme Court case WMCA, Inc., et al. v. Lomenzo, Secretary of State of New York, et al., 1965 was a landmark decision that further clarified the principle of "one person, one vote." The plaintiffs were radio station owners who sued John P. Lomenzo, the Secretary of State for New York at that time over alleged malapportionment in both houses of the state legislature which they claimed violated their Fourteenth Amendment rights to equal protection under law due to population discrepancies among districts. The court ruled in favor of WMCA and held that apportionment schemes must be based on population rather than geographical area or political subdivisions such as counties or towns to ensure fair representation for all citizens regardless their place residence within a state's borders.

In the dissenting opinion for WMCA, Inc. v. Lomenzo, Justice John Marshall Harlan II argued that the court's decision to intervene in state legislative apportionment issues was an overreach of judicial power and a violation of federalism principles. He contended that such matters should be left to state legislatures and their constituents rather than being dictated by federal courts. Furthermore, he expressed concern about the potential implications this ruling could have on future cases involving political questions or controversies related to representation ratios within states' legislative bodies.