Texas, like all other states, redistricts based on total population data from the census. A number of Texas voters argue that state legislative districts deviate from the ideal by as much as 45 percent when voting population is used. At oral argument today in Evenwel v. Abbott Justices Kennedy, frequently the Court’s “swing” vote in high-profile cases, asked whether both metrics can be used to comply with one-person, one-vote.

Since the Supreme Court in Reynolds v. Sims (1964) held that state legislative districts have to be roughly equal in population, a question has remained: what population are we talking about?

The attorney arguing that voting population should be the required metric met with resistance from all of the Court’s liberal Justices.

Justice Sotomayor brought up the policy argument that elected officials should represent everyone not just voters and the practical problem of the lack of accurate voter records. Justice Kagan pointed out that total population is favored in the Constitution; House of Representative seats are apportioned by total population. Justice Ginsburg, ever the feminist, asked whether before women had the right to vote states had mistakenly included them in redistricting.

Texas argued that as a matter of state sovereignty states should be able to continue to decide which metric they use. The conservative Justices, with the exception of normally vocal Justice Scalia who asked no questions, expressed skepticism about using total population when it created significant disparities.

Justice Kennedy asked why states couldn’t be required to rely on both total population and voter population. The United States’ attorney argued that if jurisdictions had to rely on both population metrics they would have to do so at the expense of other traditional redistricting considerations like compactness, not dividing political subdivisions, etc.

A fair amount of the argument concerned whether the American Community Survey, which is an ongoing statistical survey that samples a small percentage of the population every year, could be used reliably to determine voting population. In a nod to how this issue affects local government, the United States’ attorney emphatically argued that even if this survey produces adequate information for states, it does not do the same for local governments.  

In sum, while it is noteworthy that Justice Kennedy in particular is interested in finding a compromise between a mandatory voter population metric and a voluntary but widely accepted total population metric, it is not clear that the identified compromise will work or that the majority of the Court is interested in adopting it.

Read more commentary on the oral argument in this case on SCOTUSblog.