Justice Marshall argued that vote-dilution claims rest on the fundamental right to participate equally in elections, not merely on the Equal Protection Clause's ban on racially discriminatory classifications. Because the right to vote is fundamental, an electoral scheme that effectively denies a racial minority a meaningful opportunity to participate and elect candidates of choice may be unconstitutional based on discriminatory effect, without proof of discriminatory purpose.
He read Fortson, Burns, Whitcomb, and White v. Regester as establishing a results-focused standard. Those cases did not require proportional representation; rather, they required proof that an identifiable, politically isolated minority had less opportunity than other voters to participate in the political process and could not effectively use alternative channels of influence.
The plaintiffs met that standard. Racially polarized voting, Black voters' persistent inability to elect city commissioners, the continuing effects of pervasive discrimination, and the Commission's unresponsiveness together showed that the at-large system relegated Black citizens to political powerlessness. The system's majority-vote, numbered-post, and staggered-term features intensified that effect.
Justice Marshall also rejected the plurality's narrow Fifteenth Amendment analysis. The Amendment forbids abridgment as well as outright denial of voting rights, and a vote can be abridged when electoral structures render it ineffective because of race. He concluded that discriminatory effect should suffice under the Fifteenth Amendment as well as under § 2 of the Voting Rights Act.
Even if discriminatory intent were required, Justice Marshall believed the plurality applied an unduly rigid standard. The predictable and severe racial effects of retaining the system, combined with official indifference to Black political concerns and the history of discrimination, supported an inference that officials maintained the system because of—not merely despite—its effect on Black voters.