Timeline of redistricting cases heard by the Supreme Court of the United States

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The Supreme Court of the United States has heard numerous cases pertaining to redistricting. When the high court issues rulings in these cases, the precedents established can affect redistricting practices throughout the country.

The timeline below provides a partial list of important redistricting cases heard by the Supreme Court. Summaries of the cases and links to more extensive information are provided. To see this information in narrative form, see this article.

Timeline of redistricting cases

2020s

• 2023-2024 term — Alexander v. South Carolina State Conference of the NAACP — This case concerns a challenge to the congressional redistricting plan that the South Carolina legislature enacted after the 2020 census. In January 2023, a federal three-judge panel ruled that the state's 1st Congressional District was unconstitutional and enjoined the state from conducting future elections using its district boundaries. The panel's opinion said, "The Court finds that race was the predominant factor motivating the General Assembly’s adoption of Congressional District No. 1...Defendants have made no showing that they had a compelling state interest in the use of race in the design of Congressional District No. 1 and thus cannot survive a strict scrutiny review." Thomas Alexander (R)—in his capacity as South Carolina State Senate president—appealed the federal court's ruling, arguing: :In striking down an isolated portion of South Carolina Congressional District 1 as a racial gerrymander, the panel never even mentioned the presumption of the General Assembly’s “good faith.”...The result is a thinly reasoned order that presumes bad faith, erroneously equates the purported racial effect of a single line in Charleston County with racial predominance across District 1, and is riddled with “legal mistake[s]” that improperly relieved Plaintiffs of their “demanding” burden to prove that race was the “predominant consideration” in District 1. The U.S. Supreme Court scheduled oral argument on this case for October 11, 2023.
• June 27, 2023 — Moore v. Harper: At issue, in this case, was whether state legislatures alone are empowered by the Constitution to regulate federal elections without oversight from state courts, which is known as the independent state legislature doctrine. On November 4, 2021, the North Carolina General Assembly adopted a new congressional voting map based on 2020 Census data. The legislature, at that time, was controlled by the Republican Party. In the case Harper v. Hall (2022), a group of Democratic Party-affiliated voters and nonprofit organizations challenged the map in state court, alleging that the new map was a partisan gerrymander that violated the state constitution. On February 14, 2022, the North Carolina Supreme Court ruled that the state could not use the map in the 2022 elections and remanded the case to the trial court for further proceedings. The trial court adopted a new congressional map drawn by three court-appointed experts. The United States Supreme Court affirmed the North Carolina Supreme Court's original decision in Moore v. Harper that the state's congressional district map violated state law. In a 6-3 decision, Chief Justice John Roberts wrote that the "Elections Clause does not vest exclusive and independent authority in state legislatures to set the rules regarding federal elections.

• June 8, 2023 — Merrill v. Milligan: At issue, in this case, was the constitutionality of Alabama's 2021 redistricting plan and whether it violated Section 2 of the Voting Rights Act. A group of Alabama voters and organizations sued Secretary of State John Merrill (R) and the House and Senate redistricting chairmen, Rep. Chris Pringle (R) and Sen. Jim McClendon (R). Plaintiffs alleged the congressional map enacted on Nov. 4, 2021, by Gov. Kay Ivey (R) unfairly distributed Black voters. The plaintiffs asked the lower court to invalidate the enacted congressional map and order a new map with instructions to include a second majority-Black district. The court ruled 5-4, affirming the lower court opinion that the plaintiffs showed a reasonable likelihood of success concerning their claim that Alabama's redistricting map violated Section 2 of the Voting Rights Act.

2010s

• June 18, 2018 — Benisek v. Lamone: At issue, in this case, was the constitutionality of Maryland's congressional district map. The plaintiffs, seven state Republicans, claimed that state lawmakers altered the boundaries of the 6th District in order to dilute the impact of Republican votes. The plaintiffs alleged that this action was deliberate and effective, constituting a violation of their First Amendment right to protection from official retaliation for political beliefs. On June 18, 2018, the Supreme Court of the United States issued a per curiam opinion in Benisek v. Lamone, affirming a district court decision that had denied the plaintiffs' request for a preliminary injunction barring enforcement of a challenged congressional district map. The court determined that the plaintiffs failed to demonstrate that they would suffer irreparable harm if an injunction were not granted. The court also found that the plaintiffs had failed to demonstrate that an injunction would serve the public interest. The court did not speak to the broader question of whether partisan gerrymandering claims are justiciable.
• June 18, 2018 — Gill v. Whitford: At issue, in this case, was the constituionality of Wisconsin's state legislative district map. The plaintiffs, 12 state Democrats, challenged Wisconsin's state legislative redistricting plan, known as Act 43, as an unconstitutional partisan gerrymander in violation of the First and Fourteenth Amendments to the United States Constitution. On June 18, 2018, the court ruled that the plaintiffs had failed to demonstrate standing to bring the suit under Article III of the United States Constitution. The court's opinion, penned by Chief Justice John Roberts, did not address the broader question of whether partisan gerrymandering claims are justiciable and remanded the case to the lower court for further proceedings. Roberts was joined in the majority opinion by Associate Justices Anthony Kennedy, Ruth Bader Ginsburg, Stephen Breyer, Samuel Alito, Sonia Sotomayor, and Elena Kagan. Kagan penned a concurring opinion joined by Ginsburg, Breyer, and Sotomayor. Associate Justice Clarence Thomas penned an opinion that concurred in part with the majority opinion and in the judgment, joined by Associate Justice Neil Gorsuch.
• April 20, 2016 — Harris v. Arizona Independent Redistricting Commission: At issue was the constitutionality of state legislative districts that were created by the commission in 2012. The plaintiffs, a group of Republican voters, alleged that "the commission diluted or inflated the votes of almost two million Arizona citizens when the commission intentionally and systematically overpopulated 16 Republican districts while under-populating 11 Democrat districts." This, the plaintiffs argued, constituted a partisan gerrymander. The plaintiffs claimed that the commission placed a disproportionately large number of non-minority voters in districts dominated by Republicans; meanwhile, the commission allegedly placed many minority voters in smaller districts that tend to vote Democratic. As a result, the plaintiffs argued, more voters overall were placed in districts favoring Republicans than in those favoring Democrats, thereby diluting the votes of citizens in the Republican-dominated districts. The defendants countered that the population deviations resulted from legally defensible efforts to comply with the Voting Rights Act and obtain approval from the United States Department of Justice. On April 20, 2016, the court ruled unanimously that the plaintiffs had failed to prove that a partisan gerrymander had taken place. Instead, the court found that the commission had acted in good faith to comply with the Voting Rights Act.
• April 4, 2016 — Evenwel v. Abbott: At issue, in this case, was the constitutionality of state legislative districts in Texas. The plaintiffs, Sue Evenwel and Edward Pfenninger, argued that district populations ought to take into account only the number of registered or eligible voters residing within those districts. Total population counts have typically been used for redistricting purposes. Total population tallies include non-voting residents, such as illegal immigrants, prisoners, and children. The plaintiffs alleged that this tabulation method dilutes the voting power of citizens residing in districts that are home to smaller concentrations of non-voting residents. The court ruled 8-0 on April 4, 2016, that a state or locality can use total population counts for redistricting purposes.
• June 29, 2015 — Arizona State Legislature v. Arizona Independent Redistricting Commission: At issue, in this case, was the constitutionality of the Arizona Independent Redistricting Commission, which was established by state constitutional amendment in 2000. According to Article 1, Section 4, of the United States Constitution, "the Times, Places and Manner of holding Elections for Senators and Representatives shall be prescribed in each State by the Legislature thereof." The state legislature argued that the use of the word "legislature" in this context is literal; therefore, only a state legislature may draw congressional district lines. Meanwhile, the commission contended that the word "legislature" ought to be interpreted more broadly to mean "the legislative powers of the state," including voter initiatives and referenda. On June 29, 2015, the United States Supreme Court ruled 5-4 in favor of the Arizona Independent Redistricting Commission. The court ruled that "redistricting is a legislative function, to be performed in accordance with the state's prescriptions for lawmaking, which may include the referendum and the governor's veto."
• June 25, 2013 — Shelby County v. Holder: At issue, in this case, was the constitutionality of Section 4(b) of the Voting Rights Act of 1965, which contains a formula used to determine which governments are subject to the preclearance requirement of Section 5. Section 5 of the Voting Rights Act requires certain state and local governments to clear changes in election laws with the United States Attorney General or the United States District Court for the District of Columbia prior to their enactment. This process is known as preclearance. Section 4(b) contains a formula used to determine which governments are subject to the preclearance requirement of Section 5. On June 25, 2013, in a 5-4 decision, the Supreme Court struck down Section 4(b) as unconstitutional, as it exceeded Congress' power to enforce the Fourteenth and Fifteenth Amendments. The majority opinion was delivered by Chief Justice John Roberts, joined by Justices Antonin Scalia, Anthony Kennedy, Clarence Thomas, and Samuel Alito. The majority reasoned that the disparate treatment of the states was "based on 40-year-old facts having no logical relationship to the present day" and that a state cannot be subject to preclearance because of past discrimination. The court did not determine whether Section 5 is also unconstitutional. However, because Section 5 is only applied to jurisdictions covered by 4(b), Section 5 is effectively rendered inoperable unless Section 4(b) is replaced.

2000s

• April 28, 2004 — Vieth v. Jubelirer: The case was brought by a group of Pennsylvania Democrats who alleged that the state legislature, controlled by Republicans at the time of the 2000 redistricting cycle, had developed a congressional district map that constituted an illegal partisan gerrymander. On April 28, 2004, the court issued a split decision with no majority opinion, declining to intervene in the case. Consequently, the case established no precedent regarding claims of unconstitutional partisan gerrymandering.

1980s

• June 30, 1986 — Thornburg v. Gingles: This case rendered districts of the General Assembly of North Carolina invalid on the basis that the districts impaired the ability of black voters to elect candidates of their choice. In this ruling, the high court established three criteria for analyzing claims of vote dilution.
• June 30, 1986 — Davis v. Bandemer: The case was brought by a group of Indiana Democrats who alleged that the apportionment of Indiana's state legislature diluted the impact of Democratic votes in key districts in violation of the Equal Protection Clause of the Amendment XIV, United States Constitution. On June 30, 1986, the high court ruled that Indiana's district plans did not constitute an illegal partisan gerrymander. The court did, however, maintain that partisan gerrymandering claims are justiciable under the Equal Protection Clause (i.e., that federal courts have the right to intervene in such matters).

1960s

• June 15, 1964 — Reynolds v. Sims: The case was brought by a group of Alabama voters who alleged that the apportionment of Alabama's state legislature violated the Equal Protection Clause of the Fourteenth Amendment to United States Constitution. At the time, the Alabama Constitution required that each county have at least one representative and that there be as many senators as there were senatorial districts; these conditions created population variations between state legislative districts. On June 15, 1964, the high court ruled 8-1 in favor of the plaintiffs, finding that the United States Constitution requires "no less than substantially equal state legislative representation for all citizens."
• February 17, 1964 — Wesberry v. Sanders: The case was brought by James P. Wesberry, Jr., against Georgia Governor Carl Sanders. Wesberry alleged that the population of Georgia's Fifth Congressional District, his home district, was two to three times larger than that of other districts in the state, thereby diluting the impact of his vote relative to other Georgia residents in violation of the United States Constitution. On February 17, 1964, the court ruled 6-3 in favor of Wesberry, finding that congressional districts must have nearly equal populations in order to ensure that "as nearly as is practicable, one man's vote in a congressional election is to be worth as much as another's."
• March 26, 1962 — Baker v. Carr: The case was brought by a group of Tennessee voters who alleged that the apportionment of Tennessee's state legislature failed to account for significant population variations between districts, violating the Equal Protection Clause of the Fourteenth Amendment to United States Constitution. A federal court dismissed the complaint, finding that it lacked jurisdiction to intervene in such matters. On March 26, 1962, the Supreme Court of the United States ruled 6-2 in favor of the plaintiffs, finding that apportionment cases are justiciable (i.e., that federal courts have the right to intervene in such cases).

1940s

• June 10, 1946 — Colegrove v. Green: The case was brought by three Illinois voters who alleged that the state's congressional districts "lacked compactness of territory and approximate equality of population," violating the United States Constitution. The high court affirmed the decision of a federal district court, which had dismissed the complaint on the grounds that no requirements relating to compactness, contiguity, or equality of population existed within the canon of federal law.

See also

• Redistricting
• Gerrymandering
• State-by-state redistricting procedures