(Slip Opinion) OCTOBER TERM, 2015 1 

Syllabus 

NOTE: Where it is feasible, a syllabus (headnote) will be released, as is

being done in connection with this case, at the time the opinion is issued.

The syllabus constitutes no part of the opinion of the Court but has been

prepared by the Reporter of Decisions for the convenience of the reader. 

See United States v. Detroit Timber & Lumber Co., 200 U. S. 321, 337. 

SUPREME COURT OF THE UNITED STATES 

Syllabus 

HARRIS ET AL. v. ARIZONA INDEPENDENT 

REDISTRICTING COMMISSION ET AL. 

ON APPEAL FROM THE UNITED STATES DISTRICT COURT FOR 

THE DISTRICT OF ARIZONA 

No. 14–232. Argued December 8, 2015—Decided April 20, 2016 

After the 2010 census, Arizona’s independent redistricting commission 

(Commission), comprising two Republicans, two Democrats, and one 

Independent, redrew Arizona’s legislative districts, with guidance

from legal counsel, mapping specialists, a statistician, and a Voting

Rights Act specialist. The initial plan had a maximum population

deviation from absolute equality of districts of 4.07%, but the Commission adopted a revised plan with an 8.8% deviation on a 3-to-2

vote, with the Republican members dissenting. After the Department of Justice approved the revised plan as consistent with the Voting Rights Act, appellants filed suit, claiming that the plan’s population variations were inconsistent with the Fourteenth Amendment. 

A three-judge Federal District Court entered judgment for the Commission, concluding that the “deviations were primarily a result of

good-faith efforts to comply with the Voting Rights Act . . . even 

though partisanship played some role.” 

Held: The District Court did not err in upholding Arizona’s redistricting 

plan. Pp. 3–11.

(a) The Fourteenth Amendment’s Equal Protection Clause requires 

States to “make an honest and good faith effort to construct [legislative] districts . . . as nearly of equal population as is practicable,” 

Reynolds v. Sims, 377 U. S. 533, 577, but mathematical perfection is 

not required. Deviations may be justified by “legitimate considerations,” id., at 579, including “traditional districting principles such as

compactness [and] contiguity,” Shaw v. Reno, 509 U. S. 630, 647, as 

well as a state interest in maintaining the integrity of political subdivisions, Mahan v. Howell, 410 U. S. 315, 328, a competitive balance 

among political parties, Gaffney v. Cummings, 412 U. S. 735, 752, 
2 HARRIS v. ARIZONA INDEPENDENT 

 REDISTRICTING COMM’N 

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and, before Shelby County v. Holder, 570 U. S. ___, compliance with 

§5 of the Voting Rights Act. It was proper for the Commission to proceed on the last basis here. In addition, “minor deviations from 

mathematical equality”—i.e., deviations “under 10%,” Brown v. 

Thomson, 462 U. S. 835, 842—do not, by themselves, “make out a 

prima facie case of invidious discrimination under the Fourteenth 

Amendment [requiring] justification by the State,” Gaffney, supra, at 

745. Because the deviation here is under 10%, appellants cannot rely

upon the numbers to show a constitutional violation. Instead, they

must show that it is more probable than not that the deviation reflects the predominance of illegitimate reapportionment factors rather than “legitimate considerations.” Pp. 3–5.

(b) Appellants have failed to meet that burden here, where the record supports the District Court’s conclusion that the deviations predominantly reflected Commission efforts to achieve compliance with 

the Voting Rights Act, not to secure political advantage for the Democratic Party. To meet the Voting Rights Act’s nonretrogression requirement, a new plan, when compared to the current plan (benchmark plan), must not diminish the number of districts in which

minority groups can “elect their preferred candidates of choice” (ability-to-elect districts). A State can obtain legal assurance that it has 

satisfied this requirement if it submits its proposed plan to the Justice Department and the Department does not object to the plan. The 

record shows that the Commission redrew the initial map to ensure

that the plan had 10 ability-to-elect districts, the same number as the 

benchmark plan. But after a statistician reported that the Justice 

Department still might not agree with the plan, the Commission

changed additional boundaries, causing District 8, a Republican leaning district, to become more politically competitive. Because this record well supports the District Court’s finding that the Commission

was trying to comply with the Voting Rights Act, appellants have not

shown that it is more probable than not that illegitimate considerations were the predominant motivation for the deviations. They have

thus failed to show that the plan violates the Equal Protection 

Clause. Pp. 5–9.

(c) Appellants’ additional arguments are unpersuasive. While Arizona’s Democratic-leaning districts may be somewhat underpopulated and its Republican-leaning districts somewhat overpopulated,

these variations may reflect only the tendency of Arizona’s 2010 minority populations to vote disproportionately for Democrats and thus

can be explained by the Commission’s efforts to maintain at least 10 

ability-to-elect districts. Cox v. Larios, 542 U. S. 947, in which the 

Court affirmed a District Court’s conclusion that a Georgia reapportionment plan violated the Equal Protection Clause where its devia-
Cite as: 578 U. S. ____ (2016) 3 

Syllabus 

tion, though less than 10%, resulted from the use of illegitimate factors, is inapposite because appellants have not carried their burden 

of showing the use of illegitimate factors here. And because Shelby 

County was decided after Arizona’s plan was created, it has no bearing on the issue whether the State’s attempt to comply with the Voting Rights Act is a legitimate state interest. Pp. 9–11. 

993 F. Supp. 2d 1042, affirmed. 

BREYER, J., delivered the opinion for a unanimous Court. 
 

 

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Opinion of the Court 

NOTICE: This opinion is subject to formal revision before publication in the

preliminary print of the United States Reports. Readers are requested to

notify the Reporter of Decisions, Supreme Court of the United States, Washington, D. C. 20543, of any typographical or other formal errors, in order

that corrections may be made before the preliminary print goes to press. 

SUPREME COURT OF THE UNITED STATES 

No. 14–232 

WESLEY W. HARRIS, ET AL., APPELLANTS v. 

ARIZONA INDEPENDENT REDISTRICTING 

COMMISSION, ET AL. 

ON APPEAL FROM THE UNITED STATES DISTRICT COURT FOR 

THE DISTRICT OF ARIZONA 

[April 20, 2016] 

JUSTICE BREYER delivered the opinion of the Court. 

Appellants, a group of Arizona voters, challenge a redistricting plan for the State’s legislature on the ground 

that the plan’s districts are insufficiently equal in population. See Reynolds v. Sims, 377 U. S. 533, 577 (1964). 

Because the maximum population deviation between the

largest and the smallest district is less than 10%, the 

appellants cannot simply rely upon the numbers to show 

that the plan violates the Constitution. See Brown v. 

Thomson, 462 U. S. 835, 842 (1983). Nor have appellants 

adequately supported their contentions with other evidence. We consequently affirm a 3-judge Federal District

Court decision upholding the plan. 

I 

In 2000, Arizona voters, using the initiative process,

amended the Arizona Constitution to provide for an independent redistricting commission. See Arizona State 

Legislature v. Arizona Independent Redistricting Comm’n, 

576 U. S. ___, ___ (2015) (slip op., at 35) (upholding the 

amendment as consistent with federal constitutional and 
 

 

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Opinion of the Court 

statutory law). Each decade, the Arizona Commission on 

Appellate Court Appointments creates three slates of 

individuals: one slate of 10 Republicans, one slate of 10

Democrats, and one slate of 5 individuals not affiliated 

with any political party. The majority and minority leader 

of the Arizona Legislature each select one Redistricting 

Commission member from the first two lists. These four 

selected individuals in turn choose one member from the 

third, nonpartisan list. See Ariz. Const., Art. IV, pt. 2, 

§§1(5)–(8). Thus, the membership of the Commission

consists of two Republicans, two Democrats, and one

independent.

After each decennial census, the Commission redraws 

Arizona’s 30 legislative districts. The first step in the 

process is to create “districts of equal population in a gridlike pattern across the state.” §1(14). It then adjusts the

grid to “the extent practicable” in order to take into account the need for population equality; to maintain geographic compactness and continuity; to show respect for 

“communities of interest”; to follow locality boundaries; 

and to use “visible geographic features” and “undivided . . .

tracts.” §§1(14)(B)–(E). The Commission will “favo[r]” 

political “competitive[ness]” as long as its efforts to do so

“create no significant detriment to the other goals.” Id., 

§1(14)(F). Finally, it must adjust boundaries “as necessary” to comply with the Federal Constitution and with

the federal Voting Rights Act. §1(14)(A). 

After the 2010 census, the legislative leadership selected 

the Commission’s two Republican and two Democratic

members, who in turn selected an independent member,

Colleen Mathis. Mathis was then elected chairwoman. 

The Commission hired two counsel, one of whom they

thought of as leaning Democrat and one as leaning Republican. It also hired consultants, including mapping specialists, a statistician, and a Voting Rights Act specialist.

With the help of its staff, it drew an initial plan, based 
Cite as: 578 U. S. ____ (2016) 3 

Opinion of the Court 

upon the gridlike map, with district boundaries that produced a maximum population deviation (calculated as the 

difference between the most populated and least populated

district) of 4.07%. After changing several boundaries,

including those of Districts 8, 24, and 26, the Commission

adopted a revised plan by a vote of 3 to 2, with the two 

Republican members voting against it. In late April 2012, 

the Department of Justice approved the plan as consistent 

with the Voting Rights Act.

The next day, appellants filed this lawsuit, primarily

claiming that the plan’s population variations were inconsistent with the Fourteenth Amendment. A 3-judge Federal District Court heard the case. See 28 U. S. C. 

§2284(a) (providing for the convention of such a court 

whenever an action is filed challenging the constitutionality of apportionment of legislative districts). After a 5-day 

bench trial, the court, by a vote of 2 to 1, entered judgment

for the Commission. The majority found that “the population deviations were primarily a result of good-faith efforts 

to comply with the Voting Rights Act . . . even though 

partisanship played some role.” 993 F. Supp. 2d 1042, 

1046 (Ariz. 2014). Appellants sought direct review in this 

Court. See 28 U. S. C. §1253. We noted probable jurisdiction on June 30, 2015, and we now affirm. 

II
 

A 

The Fourteenth Amendment’s Equal Protection Clause

requires States to “make an honest and good faith effort to 

construct [legislative] districts . . . as nearly of equal population as is practicable.” Reynolds, 377 U. S., at 577. The 

Constitution, however, does not demand mathematical 

perfection. In determining what is “practicable,” we have

recognized that the Constitution permits deviation when it

is justified by “legitimate considerations incident to the 

effectuation of a rational state policy.” Id., at 579. In 
4 HARRIS v. ARIZONA INDEPENDENT 

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Opinion of the Court 

related contexts, we have made clear that in addition to 

the “traditional districting principles such as compactness 

[and] contiguity,” Shaw v. Reno, 509 U. S. 630, 647 (1993), 

those legitimate considerations can include a state interest in maintaining the integrity of political subdivisions, 

Mahan v. Howell, 410 U. S. 315, 328 (1973), or the competitive balance among political parties, Gaffney v. Cummings, 412 U. S. 735, 752 (1973). In cases decided before 

Shelby County v. Holder, 570 U. S. ___ (2013), Members of 

the Court expressed the view that compliance with §5 of

the Voting Rights Act is also a legitimate state consideration that can justify some deviation from perfect equality

of population. See League of United Latin American Citizens v. Perry, 548 U. S. 399, 518 (2006) (SCALIA, J., concurring in judgment in part and dissenting in part, joined

in relevant part by ROBERTS, C.J., THOMAS & ALITO, JJ.); 

id., at 475, n. 12 (Stevens, J., concurring in part and dissenting in part, joined in relevant part by BREYER, J.); id., 

at 485 n. 2 (Souter, J., concurring in part and dissenting in

part, joined by GINSBURG, J.); see also Vieth v. Jubelirer, 

541 U. S. 267, 284 (2004) (plurality opinion) (listing examples of traditional redistricting criteria, including “compliance with requirements of the [Voting Rights Act]”). It was 

proper for the Commission to proceed on that basis here. 

We have further made clear that “minor deviations from 

mathematical equality” do not, by themselves, “make out a

prima facie case of invidious discrimination under the

Fourteenth Amendment so as to require justification by

the State.” Gaffney, supra, at 745. We have defined as 

“minor deviations” those in “an apportionment plan with a 

maximum population deviation under 10%.” Brown, 462 

U. S., at 842. And we have refused to require States to 

justify deviations of 9.9%, White v. Regester, 412 U. S. 755, 

764 (1973), and 8%, Gaffney, 412 U. S., at 751. See also 

Fund for Accurate and Informed Representation, Inc. v. 

Weprin, 506 U. S. 1017 (1992) (summarily affirming a 
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Opinion of the Court 

District Court’s finding that there was no prima facie case

where the maximum population deviation was 9.43%).

In sum, in a case like this one, those attacking a stateapproved plan must show that it is more probable than not 

that a deviation of less than 10% reflects the predominance of illegitimate reapportionment factors rather than

the “legitimate considerations” to which we have referred

in Reynolds and later cases. Given the inherent difficulty 

of measuring and comparing factors that may legitimately 

account for small deviations from strict mathematical 

equality, we believe that attacks on deviations under 10% 

will succeed only rarely, in unusual cases. And we are not 

surprised that the appellants have failed to meet their 

burden here. 

B 

Appellants’ basic claim is that deviations in their apportionment plan from absolute equality of population reflect 

the Commission’s political efforts to help the Democratic

Party. We believe that appellants failed to prove this 

claim because, as the district court concluded, the deviations predominantly reflected Commission efforts to 

achieve compliance with the federal Voting Rights Act, not 

to secure political advantage for one party. Appellants

failed to show to the contrary. And the record bears out 

this conclusion. Cf. Anderson v. Bessemer City, 470 U. S. 

564, 573 (1985) (explaining that a district court’s factual

finding as to whether discrimination occurred will not be

set aside by an appellate court unless clearly erroneous). 

The Voting Rights Act, among other things, forbids the

use of new reapportionment plans that “would lead to a 

retrogression in the position of racial minorities with 

respect to their effective exercise of the electoral franchise.” Reno v. Bossier Parish School Bd., 520. U. S. 471, 

478 (1997). A plan leads to impermissible retrogression 

when, compared to the plan currently in effect (typically 
6 HARRIS v. ARIZONA INDEPENDENT 

 REDISTRICTING COMM’N 

Opinion of the Court 

called a “benchmark plan”), the new plan diminishes the

number of districts in which minority groups can “elect

their preferred candidates of choice” (often called “abilityto-elect” districts). See 52 U. S. C. §10304(b). A State can 

obtain legal assurance that it has satisfied the nonretrogression requirement if it submits its proposed plan

to the Federal Department of Justice, and the Department

does not object to the plan within 60 days. See 28 C. F. R. 

§§51.9, 51.52(b) (2015). While Shelby County struck down 

the §4(b) coverage formula, that decision came after the 

maps in this case were drawn.

The record in this case shows that the gridlike map that

emerged after the first step of the redistricting process

had a maximum population deviation from absolute equality of districts of 4.07%. After consulting with their Voting

Rights Act expert, their mapping consultant, and their 

statisticians, all five Commissioners agreed that they 

must try to obtain Justice Department Voting Rights Act 

“preclearance” and that the former benchmark plan contained 10 ability-to-elect districts. They consequently set

a goal of 10 such districts for the new plan. They then

went through an iterative process, involving further consultation, to adjust the plan’s initial boundaries in order to

enhance minority voting strength. In October 2011 (by a

vote of 4 to 1), they tentatively approved a draft plan with

adjusted boundaries. They believed it met their goal of 10

ability-to-elect districts. And they published the plan for 

public comment.

In the meantime, however, the Commission received a 

report from one of its statisticians suggesting that the 

Department of Justice might not agree that the new proposed plan contained 10 ability-to-elect districts. It was 

difficult to know for certain because the Justice Department did not tell States how many ability-to-elect districts

it believed were present in a benchmark plan, and neither 

did it typically explain precisely and specifically how it 
 

Cite as: 578 U. S. ____ (2016) 7 

Opinion of the Court 

would calculate the number that exist in a newly submitted plan. See 76 Fed. Reg. 7470–7471 (2011). At the same 

time, the ability-to-elect analysis was complex, involving 

more than simply adding up census figures. The Department of Justice instead conducted a “functional analysis of 

the electoral behavior within the particular . . . election 

district,” id., at 7471, and so might, for example, count as

ability-to-elect districts “crossover” districts in which 

white voters combine their votes with minorities, see 

Bartlett v. Strickland, 556 U. S. 1, 13–14 (2009). Its calculations might take into account group voting patterns, 

electoral participation, election history, and voter turnout.

See 76 Fed. Reg., 7471. The upshot was not random

decision-making but the process did create an inevitable 

degree of uncertainty. And that uncertainty could lead a

redistricting commission, as it led Arizona’s, to make

serious efforts to make certain that the districts it believed 

were ability-to-elect districts did in fact meet the criteria 

that the Department might reasonably apply. Cf. Alabama Legislative Black Caucus v. Alabama, 575 U. S. ___, 

___ (2015) (slip op., at 22) (“The law cannot insist that a 

state legislature, when redistricting, determine precisely

what percent minority population §5 demands [because] 

the standards of §5 are complex . . . . [To do so would] lay

a trap for an unwary legislature, condemning its redistricting plan as either . . . unconstitutional racial gerrymandering [or] . . . retrogressive under §5”).

As a result of the statistician’s report, the Commission 

became concerned about certain of its proposed boundaries. One of the Commission’s counsel advised that it 

would be “prudent to stay the course in terms of the ten 

districts that are in the draft map and look to . . .

strengthen them if there is a way to strengthen them.” 993

F. Supp. 2d, at 1058 (internal quotation marks omitted). 

Subsequently, the Commission adopted several changes to

the boundaries of Districts 24 and 26. It reduced the 
 

8 HARRIS v. ARIZONA INDEPENDENT 

 REDISTRICTING COMM’N 

Opinion of the Court 

populations of those districts, thereby increasing the

percentage of Hispanic voters in each. The Commission 

approved these changes unanimously. 

Changes in the boundaries of District 8, however,

proved more controversial. District 8 leaned Republican. 

A Democrat-appointed Commissioner asked the mapping 

specialist to look into modifications that might make

District 8 politically more competitive. The specialist 

returned with a draft that shifted the boundary line between District 8 and District 11 so as to keep several 

communities with high minority populations together in

District 8. The two Republican-appointed Commissioners

objected that doing so would favor Democrats by “hyperpacking” Republicans into other districts; they added

that the Commission should either favor political competitiveness throughout the State or not at all. Id., at 1059 

(internal quotation marks omitted).

The Democrat-appointed proponent of the change replied that District 8 had historically provided minority 

groups a good opportunity to elect their candidate of 

choice—an opportunity that the changes would preserve.

The Voting Rights Act specialist then said that by slightly

increasing District 8’s minority population, the Commission might be able to claim an 11th ability-to-elect district; 

and that fact would “unquestionably enhance the submission and enhance chances for preclearance.” Ibid. (internal quotation marks omitted). The Commission’s counsel 

then added that having another possible ability-to-elect 

district could be helpful because District 26 was not as

strong an ability-to-elect district as the others. See ibid. 

Only then, after the counsel and consultants argued for 

District 8 changes for the sake of Voting Rights Act preclearance, did Chairwoman Mathis support those changes.

On that basis, the Commission ultimately approved the

changes to District 8 by a vote of 3 to 2 (with the two

Republican-appointed commissioners dissenting). The 
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total population deviation among districts in this final 

map was 8.8%. While the Commission ultimately concluded that District 8 was not a true ability-to-elect district, the State’s submission to the Department of Justice

cited the changes to District 8 in support of the argument

for preclearance. On April 26, 2012, the Department of 

Justice precleared the submitted plan. 

On the basis of the facts that we have summarized, the 

District Court majority found that “the population deviations were primarily a result of good-faith efforts to comply with the Voting Rights Act . . . even though partisanship played some role.” 993 F. Supp. 2d, at 1046. This 

conclusion was well supported in the record. And as a 

result, appellants have not shown that it is more probable 

than not that illegitimate considerations were the predominant motivation behind the plan’s deviations from mathematically equal district populations—deviations that 

were under 10%. Consequently, they have failed to show 

that the Commission’s plan violates the Equal Protection

Clause as interpreted in Reynolds and subsequent cases. 

C 

The appellants make three additional arguments. First, 

they support their claim that the plan reflects unreasonable use of partisan considerations by pointing to the fact 

that almost all the Democratic-leaning districts are somewhat underpopulated and almost all the Republicanleaning districts are somewhat overpopulated. That is 

likely true. See 993 F. Supp. 2d, at 1049 (providing a

chart with percentage deviation figures by district). But 

that fact may well reflect the tendency of minority populations in Arizona in 2010 to vote disproportionately for 

Democrats. If so, the variations are explained by the 

Commission’s efforts to maintain at least 10 ability-toelect districts. The Commission may have relied on data 

from its statisticians and Voting Rights Act expert to 
10 HARRIS v. ARIZONA INDEPENDENT 

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Opinion of the Court 

create districts tailored to achieve preclearance in which 

minority voters were a larger percentage of the district

population. That might have necessitated moving other 

voters out of those districts, thereby leaving them slightly 

underpopulated. The appellants point to nothing in the

record to suggest the contrary. 

Second, the appellants point to Cox v. Larios, 542 U. S. 

947 (2004), in which we summarily affirmed a district

court’s judgment that Georgia’s reapportionment of representatives to state legislative districts violated the Equal

Protection Clause, even though the total population deviation was less than 10%. In Cox, however, unlike the present case, the district court found that those attacking the

plan had shown that it was more probable than not that 

the use of illegitimate factors significantly explained 

deviations from numerical equality among districts. The 

district court produced many examples showing that

population deviation as well as the shape of many districts

“did not result from any attempt to create districts that

were compact or contiguous, or to keep counties whole, or 

to preserve the cores of prior districts.” Id., at 949. No 

legitimate purposes could explain them. It is appellants’ 

inability to show that the present plan’s deviations and

boundary shapes result from the predominance of similarly illegitimate factors that makes Cox inapposite here.

Even assuming, without deciding, that partisanship is an 

illegitimate redistricting factor, appellants have not carried their burden. 

Third, appellants point to Shelby County v. Holder, 570 

U. S. ___ (2013), in which this Court held unconstitutional 

sections of the Voting Rights Act that are relevant to this 

case. Appellants contend that, as a result of that holding,

Arizona’s attempt to comply with the Act could not have

been a legitimate state interest. The Court decided Shelby 

County, however, in 2013. Arizona created the plan at 

issue here in 2010. At the time, Arizona was subject to 
 

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Opinion of the Court 

the Voting Rights Act, and we have never suggested the 

contrary. 

* * * 

For these reasons the judgment of the District Court is

affirmed. 

It is so ordered.