Warren, who had retired from the high tribunal just two days earlier, could have named any number of high-profile rulings: Brown v. Board of Education, which ended legal segregation in public schools; Miranda v. Arizona, which mandated that criminal suspects undergoing police interrogation be advised of their rights to counsel and against self-incrimination; Loving v. Virginia, which ended state prohibitions against interracial marriage, to list just three of the many possibilities.

Instead of these or other better-known landmarks of American constitutional law, Warren cited Baker v. Carr, the court's 1962 ruling on reapportionment, redistricting and gerrymandering that established the doctrine of "one man, one vote"—the principle, as elaborated in subsequent decisions from the early 1960s, that state and congressional electoral districts (whether rural or urban) must be roughly equal in population to ensure that individual voters have an equal voice in selecting their representatives.