As many will recall from grade school, the question of who ought to count when allocating elected representatives was central to our nation’s founding. States with slavery hoped to count the enslaved so they would get more representatives; the states without slavery argued this would be unfair since enslaved people were not considered citizens for other purposes, including voting. The grim result was the “three-fifths compromise,” which counted each enslaved person as three-fifths of a whole person, and took a civil war to finally undo. Following abolition, the Fourteenth Amendment provided that everyone—“the whole number of persons in each State”—must be counted to determine the apportionment of congressional representatives. This makes sense given that representatives represent people—citizens who can vote, but also children and immigrants working to become citizens—not just those who go to the polls.

But the Fourteenth Amendment didn’t say that states had to count everyone for drawing state legislative districts—the question in Evenwel. At argument, Justice Kagan asked about the potential incongruity that would arise if the Court agreed with the plaintiffs and required states to count only voters. The plaintiffs’ attorney, William Consovoy, conceded that the Court allowed states to use total population when it heard Reynolds v. Sims, a 1964 case that first required states to have equal electoral districts.