In what has been described as the most important “one-person, one-vote” case since the Supreme Court adopted the principle over 50 years ago, the Court held that states may apportion state legislative districts based on total population. Local governments may do the same.
The Court’s opinion in Evenwel v. Abbott is unanimous. All 50 states currently use total population to design state legislative districts; only seven adjust the census numbers “in any meaningful way.”
In Reynold v. Sims (1964) the Court established the principle of “one-person, one-vote” requiring state legislative districts to be apportioned equally so that votes would have equal weight. The question in this case is what population is relevant—total population or voter-eligible population. Total population includes numerous people who cannot vote—notably non-citizens and children.
Following the 2010 census Texas redrew its State Senate districts using total-population. The maximum total-population deviation between districts was about 8 percent (up to 10 percent is presumed constitutional); the maximum eligible-voters deviation between districts exceeded 40 percent.
Justice Ginsburg’s majority opinion concluding Texas may redistrict using total population is “based on constitutional history, this Court’s decisions, and longstanding practice.”