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.
Prior to 1962, attacks in federal courts on the drawing of boundaries for congressional 1 and legislative election districts or the apportionment of seats to previously existing units ran afoul of the political question
doctrine. 2 Baker v. Carr, 3 however, reinterpreted the doctrine to a considerable degree and opened the federal courts to voter complaints founded on unequally populated voting districts. Wesberry v. Sanders 4 found that Article I, § 2, of the Constitution required that, in the election of Members of the House of Representatives, districts were to be made up of substantially equal numbers of persons. In six decisions handed down on June 15, 1964, the Court required the alteration of the election districts for practically all the legislative bodies in the United States. 5
We hold that, as a basic constitutional standard, the Equal Protection Clause requires that the seats in both houses of a bicameral state legislature must be apportioned on a population basis. Simply stated, an individual’s right to vote for state legislators is unconstitutionally impaired when its weight is in a substantial fashion diluted when compared with the votes of citizens living in other parts of the State.
6 What was required was that each state make an honest and good faith effort to construct districts, in both houses of its legislature, as nearly of equal population as is practicable. We realize that it is a practical impossibility to arrange legislative districts so that each one has an identical number of residents, or citizens, or voters. Mathematical exactness or precision is hardly a workable constitutional requirement.
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Among the principal issues raised by these decisions were which units were covered by the principle, to what degree of exactness population equality had to be achieved, and to what other elements of the apportionment and districting process the Equal Protection Clause extended.
The first issue has largely been resolved, although a few problem areas persist. It has been held that a school board, the members of which were appointed by boards elected in units of disparate populations, and that exercised only administrative powers rather than legislative powers, was not subject to the principle of the apportionment ruling. 8 Avery v. Midland County 9 held that, when a state delegates lawmaking power to local government and provides for the election by district of the officials to whom the power is delegated, the districts must be established of substantially equal populations. But, in Hadley v. Junior College District, 10 the Court abandoned much of the limitation that was explicit in these two decisions and held that, whenever a state chooses to vest governmental functions
in a body and to elect the members of that body from districts, the districts must have substantially equal populations. The governmental functions
should not be characterized as legislative
or administrative
or necessarily important or unimportant; it is the fact that members of the body are elected from districts that triggers the application. 11
The second issue has been largely but not precisely resolved. In Swann v. Adams, 12 the Court set aside a lower court ruling for the failure of the State to present or the District Court to articulate acceptable reasons for the variations among the populations of the various legislative districts. . . . De minimis deviations are unavoidable, but variations of 30% among senate districts and 40% among house districts can hardly be deemed de minimis and none of our cases suggests that differences of this magnitude will be approved without a satisfactory explanation grounded on acceptable state policy.
Two congressional districting cases were disposed of on the basis of Swann, 13 but, although the Court ruled that no congressional districting could be approved without a good-faith effort to achieve precise mathematical equality
or the justification of each variance, no matter how small,
14 it did not apply this strict standard to state legislative redistricting. 15 And, in Abate v. Mundt, 16 the Court approved a plan for apportioning a county governing body that permitted a substantial population disparity, explaining that in the absence of a built-in bias tending to favor any particular area or interest, a plan could take account of localized factors in justifying deviations from equality that might in other circumstances invalidate a plan. 17 The total population deviation allowed in Abate was 11.9%; the Court refused, however, to extend Abate to approve a total deviation of 78% resulting from an apportionment plan providing for representation of each of New York City’s five boroughs on the New York City Board of Estimate. 18
Nine years after Reynolds v. Sims, the Court reexamined the population equality requirement of the apportionment cases. Relying upon language in prior decisions that distinguished state legislative apportionment from congressional districting as possibly justifying different standards of permissible deviations from equality, the Court held that more flexibility is constitutionally permissible with respect to the former than to the latter. 19 But it was in determining how much greater flexibility was permissible that the Court moved in new directions. First, applying the traditional standard of rationality rather than the strict test of compelling necessity, the Court held that a maximum 16.4% deviation from equality of population was justified by the state’s policy of maintaining the integrity of political subdivision lines, or according representation to subdivisions qua subdivisions, because the legislature was responsible for much local legislation. 20 Second, just as the first case demonstrates, population deviations among districts may be sufficiently large to require justification but nonetheless be justifiable and legally sustainable. It is now time to recognize . . . that minor deviations from mathematical equality among state legislative districts are insufficient to make out a prima facie case of invidious discrimination under the Fourteenth Amendment so as to require justification by the State.
21 This recognition of a de minimis deviation, below which no justification was necessary, was mandated, the Court felt, by the margin of error in census statistics, by the population change over the ten-year life of an apportionment, and by the relief it afforded federal courts by enabling them to avoid over-involvement in essentially a political process. The goal of fair and effective representation
is furthered by eliminating gross population variations among districts, but it is not achieved by mathematical equality solely. Other relevant factors are to be taken into account. 22 But when a judicially imposed plan is to be formulated upon state default, it must ordinarily achieve the goal of population equality with little more than de minimis variation,
and deviations from approximate population equality must be supported by enunciation of historically significant state policy or unique features. 23
Subsequently, in its 2016 decision in Harris v. Arizona Independent Redistricting Commission, the Court reiterated the significance of the 10% threshold in challenges to state legislative voting districts, observing that attacks on deviations under 10% will succeed only rarely, in unusual cases.
24 Instead, challengers must show that it is more probable than not
that the deviation reflects the predominance of illegitimate reapportionment factors rather than . . . legitimate considerations.
25 The Court unanimously agreed that the challengers in Harris had failed to meet this burden, as the record supported the district court’s conclusion that the deviation here—which was 8.8%—reflected the redistricting commission’s efforts to achieve compliance with the Voting Rights Act, and not to secure political advantage for the Democratic party. 26 In particular, the Court noted that the difference in population between Democratic- and Republican-leaning districts may simply reflect the residential and voting patterns of minorities, and the redistricting commission’s efforts to maintain ability-to-elect districts
(i.e., districts favorable to the election of minority candidates). 27 In the Court’s view, there was no showing of illegitimate factors
here, unlike in certain earlier cases (e.g., the creation of districts that seem to have no relation to keeping counties whole or preserving the cores of prior districts). 28 The Court further noted that its decision in Shelby County v. Holder, 29 which held unconstitutional a section of the Voting Rights Act relevant to this case, did not mean that Arizona’s attempt to comply with the Act could not have been a legitimate state interest, as Arizona created the plan at issue in 2010, and Shelby County was not decided until 2013. 30
Gerrymandering and the permissible use of multimember districts present examples of the third major issue. It is clear that racially based gerrymandering is unconstitutional under the Fifteenth Amendment, at least when it is accomplished through the manipulation of district lines. 31 Even if racial gerrymandering is intended to benefit minority voting populations, it is subject to strict scrutiny under the Equal Protection Clause 32 if race was the predominant factor motivating the legislature’s decision to place a significant number of voters within or without a particular district.
33 A challenger can show racial predominance by demonstrating that the legislature ‘subordinated’ other factors—compactness, respect for political subdivisions, partisan advantage, what have you—to 'racial considerations.'
34 Showing that a district’s bizarre
shape departs from traditional districting principles such as compactness, contiguity, and respect for political subdivision lines may serve to reinforce such a claim, 35 although a plurality of the Justices would not preclude the creation of reasonably compact
majority-minority districts in order to remedy past discrimination or to comply with the requirements of the Voting Rights Act of 1965. 36 While the Court appeared to have weakened a challenger’s ability to establish equal protection claims in the early 2000s by deferring to a legislature’s articulation of legitimate political explanations for districting decisions, and by allowing for a correlation between race and political affiliation, 37 more recent cases have shown such challenges are not entirely foreclosed. 38