Harris v. Arizona Independent Redistricting Comm'n
The Court unanimously upheld Arizona's state legislative map, ruling that the roughly 8.8% population gap between districts did not violate the Constitution because it mainly reflected good-faith efforts to comply with federal voting-rights law rather than a push to help one political party.
The decision reinforces that population differences under 10% are hard to challenge unless voters challenging a map can show the differences mostly came from improper motives, giving redistricting commissions continued flexibility when balancing minority voting power against strict numerical equality.
How it got here: A three-judge federal district court ruled for the redistricting commission after a trial, and the voters who sued appealed directly to the Supreme Court.
The Case in Depth
What happened
After the 2010 census, Arizona's independent redistricting commission, made up of two Republicans, two Democrats, and one independent, redrew the state's 30 legislative districts. A group of Arizona voters sued, arguing the final map's population differences between districts — an 8.8% gap — unfairly favored Democrats and violated the constitutional requirement that districts be roughly equal in population.
The question before the Court
Could Arizona's independent redistricting commission draw legislative districts with an 8.8% population gap between the biggest and smallest, without violating the Constitution's equality rule?
Why it matters
Redistricting commissions and state legislatures across the country can continue to accept modest population differences between districts when those differences stem from efforts to protect minority voters' ability to elect their preferred candidates. Voters challenging a map face a steep hurdle: they must prove partisan or other improper motives actually drove the numbers, not just point to the deviation itself.
What changes now
This is a final merits decision affirming the district court, so Arizona's map stands as drawn. There is no remand and no further proceedings on this claim. The ruling leaves in place the existing legal framework for challenging small population deviations in redistricting, meaning future challengers will still need to show improper motives predominated rather than relying on the deviation percentage alone.
What this does not decide
The Court did not decide whether partisanship is generally an illegitimate reason for drawing districts — it assumed without deciding that it could be, and still ruled against the challengers because they failed to prove partisanship, rather than the Voting Rights Act, actually drove the map's population differences.
How the Court got there
The legal reasoning, step by step
- The Court applied its longstanding rule that the Constitution's equal-population requirement for legislative districts does not demand mathematical perfection, and that deviations can be justified by legitimate considerations like compactness, respecting political subdivisions, or compliance with the federal Voting Rights Act.
- Because the map's maximum population deviation was under 10%, it counted as a 'minor deviation' under prior cases, meaning the voters challenging the map could not rely on the numbers alone to prove a constitutional violation.
- Instead, the challengers had to show it was more probable than not that improper motives — rather than legitimate reasons — were the main driver of the deviation, a burden the Court said would rarely be met for deviations under 10%.
- Reviewing the trial record, the Court found ample support for the district court's finding that the commission's changes were mainly aimed at satisfying the Voting Rights Act's rule against reducing minority voters' ability to elect their chosen candidates, even though partisan politics played some role.
- The Court distinguished a prior case, Cox v. Larios, where a similar under-10% deviation was struck down, because in that case the record clearly showed the deviations served no legitimate purpose at all — unlike here, where the record showed real efforts to secure federal approval under the Voting Rights Act.
- The Court also rejected the argument that a later decision striking down part of the Voting Rights Act made Arizona's earlier compliance efforts illegitimate, since that later ruling came after Arizona's map was already drawn and in effect at the time.
Doctrinal impact
Cases affected by this decision
Distinguishes Cox v. Larios (542 U.S. 947)
That case struck down a similar small deviation, but only because it was clearly driven by illegitimate motives, unlike here.