The major gerrymandering cases fall into three tracks. Federal courts still hear racial gerrymandering claims under the Fourteenth Amendment and the Voting Rights Act, with the key decisions running from Shaw v. Reno (1993) through Allen v. Milligan (2023) and Alexander v. South Carolina State Conference of the NAACP (2024). Federal courts refuse to hear partisan gerrymandering claims after Rucho v. Common Cause (2019). Those partisan fights have moved to state courts, whose authority to apply state constitutions to congressional maps was secured in Moore v. Harper (2023).
Racial Gerrymandering Cases
Racial claims are the one track where federal courts remain fully engaged. They run on two parallel rails: the Equal Protection Clause of the Fourteenth Amendment, and Section 2 of the Voting Rights Act, which forbids any voting practice that denies or abridges the right to vote on account of race.1Office of the Law Revision Counsel. 52 U.S.C. 10301 – Denial or Abridgement of Right to Vote on Account of Race or Color
Shaw v. Reno and Miller v. Johnson
The constitutional track opened with Shaw v. Reno in 1993. The Supreme Court held that a district so bizarre on its face that it cannot be understood as anything other than an effort to sort voters by race can violate equal protection.2Justia. Shaw v. Reno, 509 U.S. 630 (1993) Two years later, Miller v. Johnson sharpened the test. A challenger has to prove race was the predominant factor driving the legislature’s line-drawing, meaning racial considerations overrode traditional criteria like compactness, keeping counties whole, and respecting communities with shared interests.3Justia. Miller v. Johnson, 515 U.S. 900 (1995) Once a court finds race predominated, the map faces strict scrutiny: the state has to show a compelling reason for using race and that the lines were drawn as precisely as possible to achieve that goal.4Library of Congress. Racial Vote Dilution and Racial Gerrymandering Compliance with the Voting Rights Act is one interest courts have accepted as compelling.
Thornburg v. Gingles
Section 2 addresses a different problem: maps that dilute minority voting power by splitting a cohesive minority community across districts (cracking) or packing it into as few districts as possible. To bring a Section 2 claim, challengers must satisfy three preconditions from Thornburg v. Gingles (1986).5Justia. Thornburg v. Gingles, 478 U.S. 30 (1986) The minority group must be large enough and geographically concentrated enough to form a majority in a reasonably shaped district. The group must be politically cohesive. And the white majority must vote as a bloc consistently enough to defeat the minority group’s preferred candidates. If all three are met, the court weighs the broader circumstances to decide whether the map actually produces unequal political opportunity.
Allen v. Milligan
Allen v. Milligan reaffirmed the Gingles framework in 2023. The Supreme Court held that Alabama’s congressional map likely violated Section 2 because Black voters were sufficiently concentrated to support a second majority-Black district the legislature had refused to draw.6Supreme Court of the United States. Allen v. Milligan The decision confirmed Section 2 can require states to create majority-minority districts where the Gingles conditions exist.7Congressional Research Service. Allen v. Milligan: Supreme Court Holds That Alabama Redistricting Map Likely Violated Section 2 of the Voting Rights Act
Alexander v. South Carolina State Conference of the NAACP
A year after Milligan, the Court made racial claims noticeably harder. In Alexander (2024), the majority emphasized a strong presumption of legislative good faith.8Supreme Court of the United States. Alexander v. South Carolina State Conference of the NAACP The problem the Court flagged: in states where race and partisan preference are tightly correlated, challengers can take what is really a complaint about partisan gerrymandering, reverse-engineer the partisan data into racial data, and reframe the claim to get around Rucho’s bar on partisan cases in federal court.
The Court rejected that move. A challenger has to prove race was the predominant motive, not just a factor that correlates with the partisan motive that actually drove the map. The challenger also needs an alternative map showing that a legislature focused on its stated nonracial criteria would have drawn the district differently. Future racial gerrymandering cases will largely be won or lost in that gap between statistical correlation and proof of racial intent.
Rucho v. Common Cause: Partisan Claims Out of Federal Court
Federal courts are closed to claims that a map is unfairly partisan. The Supreme Court shut that door in Rucho v. Common Cause (2019), holding that partisan gerrymandering is a political question federal judges have no authority to resolve.9Supreme Court of the United States. Rucho v. Common Cause
The majority’s reasoning came down to a measurement problem. The Constitution doesn’t say how much partisan advantage is too much, and the Court couldn’t find a workable standard. Metrics like the efficiency gap, which measures wasted votes, got attention during the litigation, but the justices concluded no formula could reliably separate permissible political considerations from unconstitutional ones. Without a judicially manageable standard, federal intervention would amount to judges making policy choices that belong to legislatures or voters.
Rucho did not say partisan gerrymandering is constitutional. It said federal courts are the wrong forum. The decision pointed to state courts, state constitutions, independent commissions, and Congress as alternative checks, and that redirect produced the next wave of litigation.
State Court Cases After Rucho
Roughly 30 state constitutions require elections to be “free,” and about 18 of those add that elections be “equal” or “open.” Those clauses have given state courts a textual hook federal judges said they lacked.
League of Women Voters v. Commonwealth (Pennsylvania)
In 2018, the Pennsylvania Supreme Court used its Free and Equal Elections Clause to strike down the state’s 2011 congressional map, finding that extreme partisan manipulation violated voters’ rights under the state constitution. When the legislature failed to produce an acceptable replacement, the court imposed its own map. The decision became a template for partisan challenges in other states.
Harper v. Hall (North Carolina)
North Carolina shows how fragile state-court victories can be. In 2022, the state supreme court struck down legislative and congressional maps as partisan gerrymanders under the North Carolina Constitution. After two new conservative justices took office, the court granted rehearing and reversed itself in Harper v. Hall (2023), holding that partisan gerrymandering claims are nonjusticiable political questions under the state constitution and that redistricting belongs to the legislature without judicial second-guessing.10Justia Law. Harper v. Hall State constitutional litigation depends heavily on who sits on the bench.
Moore v. Harper
Moore v. Harper (2023) secured the foundation under all of this. The Supreme Court rejected the independent state legislature theory, which argued that state legislatures hold near-exclusive power over federal election rules and that state courts cannot review their redistricting decisions under state constitutions.11Supreme Court of the United States. Moore v. Harper In a 6-3 decision, the Court held that the Elections Clause does not carve out an exception to ordinary judicial review. State courts retain full authority to check congressional maps against their state constitutions. A contrary ruling would have gutted the Pennsylvania-style challenges for federal districts.
The One Person, One Vote Baseline
Every gerrymandering case sits on top of a population-equality floor set in 1964. Wesberry v. Sanders held that Article I, Section 2 requires congressional districts to be as nearly equal in population as practicable.12Justia. Wesberry v. Sanders, 376 U.S. 1 (1964) Reynolds v. Sims extended the principle to state legislative districts through the Fourteenth Amendment’s Equal Protection Clause, requiring both chambers of a state legislature to be apportioned on a population basis.13Justia. Reynolds v. Sims, 377 U.S. 533 (1964) Congressional districts demand near-mathematical precision; state legislative districts get slightly more flexibility. In Evenwel v. Abbott (2016), the Court settled who gets counted: total population, not just eligible voters, because representatives serve all residents.14Justia. Evenwel v. Abbott, 578 U.S. ___ (2016)
Commissions as an Alternative: Arizona State Legislature v. AIRC
Some states have tried to prevent gerrymandering by taking map-drawing away from the legislature. The Supreme Court blessed that approach in Arizona State Legislature v. Arizona Independent Redistricting Commission (2015), holding that the Elections Clause permits voters to create a commission by ballot initiative to draw congressional districts.15Justia. Arizona State Legislature v. Arizona Independent Redistricting Commission, 576 U.S. 787 (2015) The Court reasoned that the people are the ultimate source of legislative power and the Constitution does not require redistricting to flow exclusively through the legislature. Eleven states currently use commissions for congressional redistricting, nine of them composed entirely of non-politicians, and sixteen use commissions for state legislative maps.
The Purcell Timing Problem
Winning a gerrymandering case does not always mean a new map in time to matter. Courts are reluctant to change district lines close to an election under the Purcell principle, which treats last-minute boundary changes as a source of confusion for voters, administrators, and candidates. The closer the election, the heavier that concern weighs against intervention.
The practical effect has been large. In 2022, the Supreme Court used Purcell to reinstate Alabama’s challenged congressional map for that year’s elections even after a lower court found a likely Voting Rights Act violation. Courts similarly declined to block maps in Georgia, Arizona, and elsewhere on timing grounds. A map a court agrees is likely illegal can govern an entire election cycle if the challenge arrives too late, so the calendar often matters as much as the merits.