Fourteenth Amendment, Section 1:
All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside. No State shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States; nor shall any State deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws.
The Supreme Court has interpreted the Constitution to require that electoral districts within a redistricting map contain an approximately equal number of persons.1 This requirement is referred to as the “equality standard” or the principle of “one person, one vote.” 2 In 1964, the Court in Wesberry v. Sanders3 interpreted provisions of the Constitution stating that Representatives are to be chosen “by the People of the several States” 4 and “apportioned among the several States . . . according to their respective Numbers” 5 to require that “as nearly as is practicable, one man’s vote in a congressional election is to be worth as much as another’s.” 6 Later in 1964, the Court in Reynolds v. Sims7 extended the equality standard to apply to state legislative redistricting under the Equal Protection Clause, requiring all participants in an election “to have an equal vote.” 8
In a series of rulings since 1964, the Supreme Court has described the extent to which precise or ideal mathematical population equality among electoral districts is required.9 Ideal or precise equality is the average population that each district would contain if a state population were evenly distributed across all districts; and the total or “maximum population deviation” refers to the percentage difference from the ideal population between the most populated district and the least populated district in a redistricting map.10 In 1967, the Court announced that while “[d]e minimis deviations are unavoidable, . . . variations of 30% among [state legislative] senate districts and 40% among [state legislative] house districts can hardly be deemed de minimis,” emphasizing that none of the Court’s prior case law has approved of such large differences.11 By contrast, evaluating the principle of equal protection in the context of a county governing body, the Court approved of a population disparity among districts of 11.9% because of a “long tradition of overlapping functions and dual personnel” in the county government and because the map did not intrinsically contain “bias tending to favor particular political interests or geographic areas.” 12
Nine years after deciding Reynolds v. Sims, the Court continued to clarify the population equality requirement. Underscoring that less deviation from precise population equality is permissible for congressional districts than is permissible for state legislative districts, in 1973, the Court upheld a state legislative redistricting map that contained a total population percentage deviation of 16.4%.13 The Court reached its decision by determiing, in part, that the challenged map “may reasonably be said to advance the rational state policy of respecting the boundaries of political subdivisions.” 14 In 1975, in holding that a 20% population deviation did not comport with standards of equal protection, the Court observed that a deviation of such “magnitude” cannot be constitutionally permissible without “significant state policies or other acceptable considerations that require adoption of a plan with so great a variance.” 15 In 2016, the Court held that challengers to maps with a “minor” deviation of less than 10% must show that it is “more probable than not” that the deviation “reflects the predominance of illegitimate reapportionment factors,” concluding “that attacks on deviations under 10% will succeed only rarely, in unusual cases.” 16 Also in 2016, the Court rejected the argument that the Equal Protection Clause prohibits states from using total population, instead of total voting population, in drawing state legislative redistricting maps.17
- Prior to the 1960s, the Supreme Court determined that constitutional challenges to redistricting plans presented nonjusticiable political questions that were most appropriately addressed by the political branches of government. See, e.g., Colegrove v. Green, 328 U.S. 549, 552 (1946) (characterizing the dispute as presenting the Court with “what is beyond its competence to grant” because the issue is “of a peculiarly political nature and therefore not meet for judicial determination.” ); Smiley v. Holm, 285 U.S. 355 (1932); Wood v. Broom, 287 U.S. 1 (1932); Green, 328 U.S. 549, Cook v. Fortson, 329 U.S. 675 (1946); Colegrove v. Barrett, 330 U.S. 804 (1947); MacDougall v. Green, 335 U.S. 281 (1948); South v. Peters, 339 U.S. 276 (1950); and Hartsfield v. Sloan, 357 U.S. 916 (1958). In 1962, the Court held such challenges justiciable. See Baker v. Carr, 369 U.S. 186, 217 (1962).
- See Gray v. Sanders, 372 U.S. 368, 381 (1963) (holding that the conception of political equality means one person, one vote).
- 376 U.S. 1 (1964).
- U.S. Const. art. I, § 2, cl. 1. See ArtI.S2.C1.1 Congressional Districting.
- U.S. Const. amend. XIV, § 2. cl. 1.
- Wesberry, 376 U.S. at 7–8.
- 377 U.S. 533 (1964).
- Id. at 557–58. See also WMCA, Inc. v. Lomenzo, 377 U.S. 633 (1964); Md. Comm. for Fair Representation v. Tawes, 377 U.S. 656 (1964); Donis v. Mann, 377 U.S. 678 (1964); Roman v. Sincock, 377 U.S. 695 (1964); Lucas v. Forty-Fourth Gen. Assembly of Colorado, 377 U.S. 713, 736 (1964) (holding that “[a]n individual’s constitutionally protected right to cast an equally weighed vote cannot be denied even by a vote of a majority of a State’s electorate, if the apportionment scheme adopted by the voters fails to measure up to the requirements of the Equal Protection Clause.” ).
- See also Sailors v. Bd. of Educ. of the Cnty. of Kent, 387 U.S. 105, 111 (1967) (holding that, as a threshold issue, the Equal Protection Clause did not apply to a state law whereby residents elected local school boards, which in turn, through delegates, appointed members to county school boards without regard to the population represented because the county school board members were not elected and the board functions were nonlegislative); Avery v. Midland Cnty., 390 U.S. 474, 481 (1968) (holding that when a state delegates lawmaking power to a local government, providing for election by districts, the districts are subject to the principle of equal protection because there is “little difference . . . between the exercise of state power through legislatures and its exercise by elected officials in the cities, towns, and counties.” ); Hadley v. Junior Coll. Dist., 397 U.S. 50, 56 (1970) (holding that whenever a state chooses to vest “governmental functions” in a body and to elect the members of that body from districts, the districts are subject to the principle of equal protection). In Hadley, the Court acknowledged distinguishable cases “in which a State elects certain functionaries whose duties are so far removed from normal governmental activities and so disproportionately affect different groups” that the principle of equal protection does not apply. Id. at 56. See, e.g., Salyer Land Co. v. Tulare Water Storage Dist., 410 U.S. 719 (1973); Associated Enters. v. Toltec Watershed Improvement Dist., 410 U.S. 743 (1973); Ball v. James, 451 U.S. 355 (1981); in the context of judicial districts, see, e.g., Wells v. Edwards, 347 F. Supp. 453 (M.D. La. 1972) (three-judge court), aff’d, 409 U.S. 1095 (1973) (per curiam).
- See, e.g., Brown v. Thomson, 462 U.S. 835, 842–43 (1983). See also, e.g., Gaffney v. Cummings, 412 U.S. 735 (1973) (upholding a Connecticut legislative redistricting plan with a total maximum population deviation of 7.83%). But see Cox v. Larios, 542 U.S. 947 (2004) (upholding the invalidation of a state legislative redistricting plan with a total maximum population deviation of 9.98%).
- Swann v. Adams, 385 U.S. 440, 444 (1967). See also Connor v. Williams, 404 U.S. 549, 550 (1972) (distinguishing between the standards of population equality applicable to state legislative districts and congressional districts); Kilgarlin v. Hill, 386 U.S. 120 (1967); Duddleston v. Grills, 385 U.S. 455 (1967).
- Abate v. Mundt, 403 U.S. 182, 187 (1971). But see Bd. of Estimate of N.Y. v. Morris, 489 U.S. 688 (1989) (invalidating a redistricting map providing for representation in each of New York City’s five boroughs on the New York City Board of Estimate that contained a higher population disparity).
- See Mahan v. Howell, 410 U.S. 315, 319, 332–33 (1973). See also White v. Regester, 412 U.S. 755, 763–64 (1973) (upholding a state legislative redistricting map with a total maximum deviation of 9.9% among house districts and an average deviation of 1.82%); Connor v. Finch, 431 U.S. 407, 417–18 (1977) (invalidating a state legislative redistricting map with a maximum population deviation in the senate districts of 16.5% and in the house districts of 19.3%).
- Mahan, 410 U.S. at 328.
- Chapman v. Meier, 420 U.S. 1, 24 (1975). See also Summers v. Cenarrusa, 413 U.S. 906 (1973). (vacating and remanding for further consideration the approval of a 19.4% deviation). But see Voinovich v. Quilter, 507 U.S. 146 (1993) (vacating and remanding for further consideration the rejection of a deviation in excess of 10% intended to preserve political subdivisions).
- Harris v. Ariz. Indep. Redistricting Comm’n, 578 U.S. 253, 259 (2016).
- See Evenwel v. Abbott, 578 U.S. 54, 74 (2016). The Court declined, however, to determine that redistricting based on total population is constitutionally required, noting that the Court has upheld the use of districts based on voting population. See id. at 60 (citing Burns v. Richardson, 384 U.S. 73, 93–94 (1966) (upholding a Hawaii redistricting map that was based on the registered-voter population)).