This morning, the unanimous Supreme Court ruled that Texas was constitutionally justified in drawing state electoral districts based on total population, even if this meant that great disparatives result among districts in numbers of voters. This was the case of Evenwel v. Abbott, in which Cato had filed a brief arguing that the plaintiff-voters’ proposed “citizen of voting age population” (CVAP) metric was a much better one to use when applying the “one-person, one-vote” standard.

While the eight-justice Court managed to achieve rare unanimity in an election-law case, at least in judgment, it did so only by declining to address the elephant in the voting booth. The Court failed to fill the gaping hole in its voting-rights jurisprudence: the question whether the venerable “one-person, one-vote” principle requires equalizing people or voters (or both) when crafting representational districts.

Still, the ruling leaves open to the states the ability to experiment further with populations considered in drawing district lines both for their own legislatures and federal House seats. Some states already exclude aliens, nonpermanent residents, nonresident military personnel, inmates who were not state residents prior to incarceration, and other non-permanent or non-voting populations.

States like Texas where total-population allocations continue to diverge from eligible-voter allocations—resulting in great disparities of voters between districts—should indeed try to ensure that each vote has the same relative weight, forcing the Supreme Court’s hand in some future case. Regardless of the outcome in that eventual case, however, jurists and political scientists should take heed of Justice Alito’s concurring opinion, which concisely explains why the “federal analogy” to the Constitution’s apportionment of House seats among states is inapposite to the question posed in Evenwel regarding redistricting.

For more background on the case, see my SCOTUSblog essay.