APPEAL FROM THE UNITED STATES DISTRICT COURT FOR THE EASTERN DISTRICT OF NORTH CAROLINA.
Brennan, J., announced the judgment of the Court and delivered the opinion of the Court with respect to Parts I, II, III-A, III-B, IV-A, and V, in which White, Marshall, Blackmun, and Stevens, JJ., joined, an opinion with respect to Part III-C, in which Marshall, Blackmun, and Stevens, JJ., joined, and an opinion with respect to Part IV-B, in which White, J., joined. White, J., filed a concurring opinion, post, p. 82. O'connor, J., filed an opinion concurring in the judgment, in which Burger, C. J., Powell and Rehnquist, JJ., joined, post, p. 83. Stevens, J., filed an opinion concurring in part and dissenting in part, in which Marshall and Blackmun, JJ., joined, post, p. 106.
JUSTICE BRENNAN announced the judgment of the Court and delivered the opinion of the Court with respect to Parts I, II, III-A, III-B, IV-A, and V, an opinion with respect to Part III-C, in which JUSTICE MARSHALL, JUSTICE BLACKMUN, and JUSTICE STEVENS join, and an opinion with respect to Part IV-B, in which JUSTICE WHITE joins.
This case requires that we construe for the first time § 2 of the Voting Rights Act of 1965, as amended June 29, 1982. 42 U. S. C. § 1973. The specific question to be decided is whether the three-judge District Court, convened in the Eastern District of North Carolina pursuant to 28 U. S. C. § 2284(a) and 42 U. S. C. § 1973c, correctly held that the use in a legislative redistricting plan of multimember districts in five North Carolina legislative districts violated § 2 by impairing the opportunity of black voters "to participate in the political process and to elect representatives of their choice." § 2(b), 96 Stat. 134.
In April 1982, the North Carolina General Assembly enacted a legislative redistricting plan for the State's Senate
and House of Representatives. Appellees, black citizens of North Carolina who are registered to vote, challenged seven districts, one single-member*fn1 and six multimember*fn2 districts, alleging that the redistricting scheme impaired black citizens' ability to elect representatives of their choice in violation of the Fourteenth and Fifteenth Amendments to the United States Constitution and of § 2 of the Voting Rights Act.*fn3
After appellees brought suit, but before trial, Congress amended § 2. The amendment was largely a response to this Court's plurality opinion in Mobile v. Bolden, 446 U.S. 55 (1980), which had declared that, in order to establish a violation either of § 2 or of the Fourteenth or Fifteenth Amendments, minority voters must prove that a contested electoral mechanism was intentionally adopted or maintained by state officials for a discriminatory purpose. Congress substantially revised § 2 to make clear that a violation could be proved by showing discriminatory effect alone and to establish as the relevant legal standard the "results test," applied by this Court in White v. Regester, 412 U.S. 755 (1973), and by other federal courts before Bolden, supra. S. Rep. No. 97-417, p. 28 (1982) (hereinafter S. Rep.).
Section 2, as amended, 96 Stat. 134, reads as follows:
"(a) No voting qualification or prerequisite to voting or standard, practice, or procedure shall be imposed or applied by any State or political subdivision in a manner which results in a denial or abridgement of the right of any citizen of the United States to vote on account of race or color, or in contravention of the guarantees set forth in section 4(f)(2), as provided in subsection (b).
"(b) A violation of subsection (a) is established if, based on the totality of circumstances, it is shown that the political processes leading to nomination or election in the State or political subdivision are not equally open to participation by members of a class of citizens protected by subsection (a) in that its members have less opportunity than other members of the electorate to participate in the political process and to elect representatives of their choice. The extent to which members of a protected class have been elected to office in the State or political subdivision is one circumstance which may be considered: Provided, That nothing in this section establishes a right to have members of a protected class elected in numbers equal to their proportion in the population." Codified at 42 U. S. C. § 1973.
The Senate Judiciary Committee majority Report accompanying the bill that amended § 2 elaborates on the circumstances that might be probative of a § 2 violation, noting the following "typical factors":*fn4
"1. the extent of any history of official discrimination in the state or political subdivision that touched the right of
the members of the minority group to register, to vote, or otherwise to participate in the democratic process;
"2. the extent to which voting in the elections of the state or political subdivision is racially polarized;
"3. the extent to which the state or political subdivision has used unusually large election districts, majority vote requirements, anti-single shot provisions, or other voting practices or procedures that may enhance the opportunity for discrimination against the minority group;
"4. if there is a candidate slating process, whether the members of the minority group have been denied access to that process;
"5. the extent to which members of the minority group in the state or political subdivision bear the effects of discrimination in such areas as education, employment and health, which hinder their ability to participate effectively in the political process;
"6. whether political campaigns have been characterized by overt or subtle racial appeals;
"7. the extent to which members of the minority group have been elected to public office in the jurisdiction.
"Additional factors that in some cases have had probative value as part of plaintiffs' evidence to establish a violation are:
"whether there is a significant lack of responsiveness on the part of elected officials to the particularized needs of the members of the minority group.
"whether the policy underlying the state or political subdivision's use of such voting qualification, prerequisite to voting, or standard, practice or procedure is tenuous." S. Rep., at 28-29.
The District Court applied the "totality of the circumstances" test set forth in § 2(b) to appellees' statutory claim, and, relying principally on the factors outlined in the Senate
Report, held that the redistricting scheme violated § 2 because it resulted in the dilution of black citizens' votes in all seven disputed districts. In light of this conclusion, the court did not reach appellees' constitutional claims. Gingles v. Edmisten, 590 F.Supp. 345 (EDNC 1984).
Preliminarily, the court found that black citizens constituted a distinct population and registered-voter minority in each challenged district. The court noted that at the time the multimember districts were created, there were concentrations of black citizens within the boundaries of each that were sufficiently large and contiguous to constitute effective voting majorities in single-member districts lying wholly within the boundaries of the multimember districts. With respect to the challenged single-member district, Senate District No. 2, the court also found that there existed a concentration of black citizens within its boundaries and within those of adjoining Senate District No. 6 that was sufficient in numbers and in contiguity to constitute an effective voting majority in a single-member district. The District Court then proceeded to find that the following circumstances combined with the multimember districting scheme to result in the dilution of black citizens' votes.
First, the court found that North Carolina had officially discriminated against its black citizens with respect to their exercise of the voting franchise from approximately 1900 to 1970 by employing at different times a poll tax, a literacy test, a prohibition against bullet (single-shot) voting,*fn5
and designated seat plans*fn6 for multimember districts. The court observed that even after the removal of direct barriers to black voter registration, such as the poll tax and literacy test, black voter registration remained relatively depressed; in 1982 only 52.7% of age-qualified blacks statewide were registered to vote, whereas 66.7% of whites were registered. The District Court found these statewide depressed levels of black voter registration to be present in all of the disputed districts and to be traceable, at least in part, to the historical pattern of statewide official discrimination.
Second, the court found that historic discrimination in education, housing, employment, and health services had resulted in a lower socioeconomic status for North Carolina blacks as a group than for whites. The court concluded that this lower status both gives rise to special group interests and hinders blacks' ability to participate effectively in the political process and to elect representatives of their choice.
Third, the court considered other voting procedures that may operate to lessen the opportunity of black voters to elect candidates of their choice. It noted that North Carolina has a majority vote requirement for primary elections and, while acknowledging that no black candidate for election to the State General Assembly had failed to win solely because of this requirement, the court concluded that it nonetheless presents a continuing practical impediment to the opportunity of black voting minorities to elect candidates of their choice. The court also remarked on the fact that North Carolina does not have a subdistrict residency requirement for members of the General Assembly elected from multimember
districts, a requirement which the court found could offset to some extent the disadvantages minority voters often experience in multimember districts.
Fourth, the court found that white candidates in North Carolina have encouraged voting along color lines by appealing to racial prejudice. It noted that the record is replete with specific examples of racial appeals, ranging in style from overt and blatant to subtle and furtive, and in date from the 1890's to the 1984 campaign for a seat in the United States Senate. The court determined that the use of racial appeals in political campaigns in North Carolina persists to the present day and that its current effect is to lessen to some degree the opportunity of black citizens to participate effectively in the political processes and to elect candidates of their choice.
Fifth, the court examined the extent to which blacks have been elected to office in North Carolina, both statewide and in the challenged districts. It found, among other things, that prior to World War II, only one black had been elected to public office in this century. While recognizing that "it has now become possible for black citizens to be elected to office at all levels of state government in North Carolina," 590 F.Supp., at 367, the court found that, in comparison to white candidates running for the same office, black candidates are at a disadvantage in terms of relative probability of success. It also found that the overall rate of black electoral success has been minimal in relation to the percentage of blacks in the total state population. For example, the court noted, from 1971 to 1982 there were at any given time only two-to-four blacks in the 120-member House of Representatives -- that is, only 1.6% to 3.3% of House members were black. From 1975 to 1983 there were at any one time only one or two blacks in the 50-member State Senate -- that is, only 2% to 4% of State Senators were black. By contrast, at the time of the District Court's opinion, blacks constituted about 22.4% of the total state population.
With respect to the success in this century of black candidates in the contested districts, see also Appendix B to opinion, post, p. 82, the court found that only one black had been elected to House District 36 -- after this lawsuit began. Similarly, only one black had served in the Senate from District 22, from 1975-1980. Before the 1982 election, a black was elected only twice to the House from District 39 (part of Forsyth County); in the 1982 contest two blacks were elected. Since 1973 a black citizen had been elected each 2-year term to the House from District 23 (Durham County), but no black had been elected to the Senate from Durham County. In House District 21 (Wake County), a black had been elected twice to the House, and another black served two terms in the State Senate. No black had ever been elected to the House or Senate from the area covered by House District No. 8, and no black person had ever been elected to the Senate from the area covered by Senate District No. 2.
The court did acknowledge the improved success of black candidates in the 1982 elections, in which 11 blacks were elected to the State House of Representatives, including 5 blacks from the multimember districts at issue here. However, the court pointed out that the 1982 election was conducted after the commencement of this litigation. The court found the circumstances of the 1982 election sufficiently aberrational and the success by black candidates too minimal and too recent in relation to the long history of complete denial of elective opportunities to support the conclusion that black voters' opportunities to elect representatives of their choice were not impaired.
Finally, the court considered the extent to which voting in the challenged districts was racially polarized. Based on statistical evidence presented by expert witnesses, supplemented to some degree by the testimony of lay witnesses, the court found that all of the challenged districts exhibit severe and persistent racially polarized voting.
Based on these findings, the court declared the contested portions of the 1982 redistricting plan violative of § 2 and enjoined appellants from conducting elections pursuant to those portions of the plan. Appellants, the Attorney General of North Carolina and others, took a direct appeal to this Court, pursuant to 28 U. S. C. § 1253, with respect to five of the multimember districts -- House Districts 21, 23, 36, and 39, and Senate District 22. Appellants argue, first, that the District Court utilized a legally incorrect standard in determining whether the contested districts exhibit racial bloc voting to an extent that is cognizable under § 2. Second, they contend that the court used an incorrect definition of racially polarized voting and thus erroneously relied on statistical evidence that was not probative of polarized voting. Third, they maintain that the court assigned the wrong weight to evidence of some black candidates' electoral success. Finally, they argue that the trial court erred in concluding that these multimember districts result in black citizens having less opportunity than their white counterparts to participate in the political process and to elect representatives of their choice. We noted probable jurisdiction, 471 U.S. 1064 (1985), and now affirm with respect to all of the districts except House District 23. With regard to District 23, the judgment of the District Court is reversed.
SECTION 2 AND VOTE DILUTION THROUGH USE OF MULTIMEMBER DISTRICTS
An understanding both of § 2 and of the way in which multimember districts can operate to impair blacks' ability to elect representatives of their choice is prerequisite to an evaluation of appellants' contentions. First, then, we review amended § 2 and its legislative history in some detail. Second, we explain the theoretical basis for appellees' claim of vote dilution.
SECTION 2 AND ITS LEGISLATIVE HISTORY
Subsection 2(a) prohibits all States and political subdivisions from imposing any voting qualifications or prerequisites to voting, or any standards, practices, or procedures which result in the denial or abridgment of the right to vote of any citizen who is a member of a protected class of racial and language minorities. Subsection 2(b) establishes that § 2 has been violated where the "totality of circumstances" reveal that "the political processes leading to nomination or election . . . are not equally open to participation by members of a [protected class] . . . in that its members have less opportunity than other members of the electorate to participate in the political process and to elect representatives of their choice." While explaining that "[the] extent to which members of a protected class have been elected to office in the State or political subdivision is one circumstance which may be considered" in evaluating an alleged violation, § 2(b) cautions that "nothing in [§ 2] establishes a right to have members of a protected class elected in numbers equal to their proportion in the population."
The Senate Report which accompanied the 1982 amendments elaborates on the nature of § 2 violations and on the proof required to establish these violations.*fn7 First and foremost, the Report dispositively rejects the position of the plurality in Mobile v. Bolden, 446 U.S. 55 (1980), which
required proof that the contested electoral practice or mechanism was adopted or maintained with the intent to discriminate against minority voters.*fn8 See, e. g., S. Rep., at 2, 15-16, 27. The intent test was repudiated for three principal reasons -- it is "unnecessarily divisive because it involves charges of racism on the part of individual officials or entire communities," it places an "inordinately difficult" burden of proof on plaintiffs, and it "asks the wrong question." Id., at 36. The "right" question, as the Report emphasizes repeatedly, is whether "as a result of the challenged practice or structure plaintiffs do not have an equal opportunity to participate in the political processes and to elect candidates of their choice."*fn9 Id., at 28. See also id., at 2, 27, 29, n. 118, 36.
In order to answer this question, a court must assess the impact of the contested structure or practice on minority electoral opportunities "on the basis of objective factors." Id., at 27. The Senate Report specifies factors which typically may be relevant to a § 2 claim: the history of voting-related discrimination in the State or political subdivision; the extent to which voting in the elections of the State or political
subdivision is racially polarized; the extent to which the State or political subdivision has used voting practices or procedures that tend to enhance the opportunity for discrimination against the minority group, such as unusually large election districts, majority vote requirements, and prohibitions against bullet voting; the exclusion of members of the minority group from candidate slating processes; the extent to which minority group members bear the effects of past discrimination in areas such as education, employment, and health, which hinder their ability to participate effectively in the political process; the use of overt or subtle racial appeals in political campaigns; and the extent to which members of the minority group have been elected to public office in the jurisdiction. Id., at 28-29; see also supra, at 36-37. The Report notes also that evidence demonstrating that elected officials are unresponsive to the particularized needs of the members of the minority group and that the policy underlying the State's or the political subdivision's use of the contested practice or structure is tenuous may have probative value. Id., at 29. The Report stresses, however, that this list of typical factors is neither comprehensive nor exclusive. While the enumerated factors will often be pertinent to certain types of § 2 violations, particularly to vote dilution claims,*fn10 other factors may also be relevant and may be considered. Id., at 29-30. Furthermore, the Senate Committee observed that "there is no requirement that any particular number of factors be proved, or that a majority of them point one way or the other." Id., at 29. Rather, the Committee determined that "the question whether the political processes are 'equally open' depends upon a searching practical evaluation of the 'past and present reality,'" id., at 30 (footnote omitted), and on a "functional" view of the political process. Id., at 30, n. 120.
Although the Senate Report espouses a flexible, fact-intensive test for § 2 violations, it limits the circumstances under which § 2 violations may be proved in three ways. First, electoral devices, such as at-large elections, may not be considered per se violative of § 2. Plaintiffs must demonstrate that, under the totality of the circumstances, the devices result in unequal access to the electoral process. Id., at 16. Second, the conjunction of an allegedly dilutive electoral mechanism and the lack of proportional representation alone does not establish a violation. Ibid. Third, the results test does not assume the existence of racial bloc voting; plaintiffs must prove it. Id., at 33.
VOTE DILUTION THROUGH THE USE OF MULTIMEMBER DISTRICTS
Appellees contend that the legislative decision to employ multimember, rather than single-member, districts in the contested jurisdictions dilutes their votes by submerging them in a white majority,*fn11 thus impairing their ability to elect representatives of their choice.*fn12
The essence of a § 2 claim is that a certain electoral law, practice, or structure interacts with social and historical conditions to cause an inequality in the opportunities enjoyed by black and white voters to elect their preferred representatives. This Court has long recognized that multimember districts and at-large voting schemes may "'operate to minimize or cancel out the voting strength of racial [minorities in] the voting population.'"*fn13 Burns v. Richardson, 384 U.S. 73, 88
(1966) (quoting Fortson v. Dorsey, 379 U.S. 433, 439 (1965)). See also Rogers v. Lodge, 458 U.S. 613, 617 (1982); White v. Regester, 412 U.S., at 765; Whitcomb v. Chavis, 403 U.S. 124, 143 (1971). The theoretical basis for this type of impairment is that where minority and majority voters consistently prefer different candidates, the majority, by virtue of its numerical superiority, will regularly defeat the choices of minority voters.*fn14 See, e. g., Grofman, Alternatives, in Representation and Redistricting Issues 113-114. Multimember districts and at-large election schemes, however, are not per se violative of minority voters' rights. S. Rep., at 16. Cf. Rogers v. Lodge, supra, at 617; Regester, supra, at 765; Whitcomb, supra, at 142. Minority voters who contend that the multimember form of districting violates § 2 must prove that the use of a multimember electoral structure operates to minimize or cancel out their ability to elect their preferred candidates. See, e. g., S. Rep., at 16.
While many or all of the factors listed in the Senate Report may be relevant to a claim of vote dilution through submergence in multimember districts, unless there is a conjunction of the following circumstances, the use of multimember districts generally will not impede the ability of minority voters to elect representatives of their choice.*fn15 Stated succinctly,
a bloc voting majority must usually be able to defeat candidates supported by a politically cohesive, geographically insular minority group. Bonapfel 355; Blacksher & Menefee 34; Butler 903; Carpeneti 696-699; Davidson, Minority Vote Dilution: An Overview (hereinafter Davidson), in Minority Vote Dilution 4; Grofman, Alternatives 117. Cf. Bolden, 446 U.S., at 105, n. 3 (MARSHALL, J., dissenting) ("It is obvious
that the greater the degree to which the electoral minority is homogeneous and insular and the greater the degree that bloc voting occurs along majority-minority lines, the greater will be the extent to which the minority's voting power is diluted by multimember districting"). These circumstances are necessary preconditions for multimember districts to operate to impair minority voters' ability to elect representatives of their choice for the following reasons. First, the minority group must be able to demonstrate that it is sufficiently large and geographically compact to constitute a majority in a single-member district.*fn16 If it is not, as would be the case in a substantially integrated district, the multimember form of the district cannot be responsible for minority voters' inability to elect its candidates.*fn17 Cf. Rogers, 458 U.S., at 616.
See also, Blacksher & Menefee 51-56, 58; Bonapfel 355; Carpeneti 696; Davidson 4; Jewell 130. Second, the minority group must be able to show that it is politically cohesive. If the minority group is not politically cohesive, it cannot be said that the selection of a multimember electoral structure thwarts distinctive minority group interests. Blacksher & Menefee 51-55, 58-60, and n. 344; Carpeneti 696-697; Davidson 4. Third, the minority must be able to demonstrate that the white majority votes sufficiently as a bloc to enable it -- in the absence of special circumstances, such as the minority candidate running unopposed, see, infra, at 57, and n. 26 -- usually to defeat the minority's preferred candidate. See, e. g., Blacksher & Menefee 51, 53, 56-57, 60. Cf. Rogers, supra, at 616-617; Whitcomb, 403 U.S., at 158-159; McMillan v. Escambia County, Fla., 748 F.2d 1037, 1043 (CA5 1984). In establishing this last circumstance, the minority group demonstrates that submergence in a white multimember district impedes its ability to elect its chosen representatives.
Finally, we observe that the usual predictability of the majority's success distinguishes structural dilution from the mere loss of an occasional election. Cf. Davis v. Bandemer, post, at 131-133, 139-140 (opinion of WHITE, J.); Bolden, supra, at 111, n. 7 (MARSHALL, J., dissenting); Whitcomb, supra, at 153. See also Blacksher & Menefee 57, n. 333; Note, Geometry and Geography: Racial Gerrymandering and the Voting Rights Act, 94 Yale L. J. 189, 200, n. 66 (1984) (hereinafter Note, Geometry and Geography).
RACIALLY POLARIZED VOTING
Having stated the general legal principles relevant to claims that § 2 has been violated through the use of multimember districts, we turn to the arguments of appellants and of the United States as amicus curiae addressing racially polarized voting.*fn18 First, we describe the District Court's treatment of racially polarized voting. Next, we consider appellants' claim that the District Court used an incorrect legal standard to determine whether racial bloc voting in the contested districts was sufficiently severe to be cognizable as an element of a § 2 claim. Finally, we consider appellants' contention that the trial court employed an incorrect definition of racially polarized voting and thus erroneously relied on statistical evidence that was not probative of racial bloc voting.
THE DISTRICT COURT'S TREATMENT OF RACIALLY POLARIZED VOTING
The investigation conducted by the District Court into the question of racial bloc voting credited some testimony of lay witnesses, but relied principally on statistical evidence presented by appellees' expert witnesses, in particular that offered by Dr. Bernard Grofman. Dr. Grofman collected and evaluated data from 53 General Assembly primary and general elections involving black candidacies. These elections were held over a period of three different election years in the six originally challenged multimember districts.*fn19 Dr. Grofman subjected the data to two complementary methods of analysis -- extreme case analysis and bivariate ecological
regression analysis*fn20 -- in order to determine whether blacks and whites in these districts differed in their voting behavior. These analytic techniques yielded data concerning the voting patterns of the two races, including estimates of the percentages of members of each race who voted for black candidates.
The court's initial consideration of these data took the form of a three-part inquiry: did the data reveal any correlation between the race of the voter and the selection of certain candidates; was the revealed correlation statistically significant; and was the difference in black and white voting patterns "substantively significant"? The District Court found that blacks and whites generally preferred different candidates and, on that basis, found voting in the districts to be racially correlated.*fn21 The court accepted Dr. Grofman's expert opinion that the correlation between the race of the voter and the voter's choice of certain candidates was statistically significant.*fn22 Finally, adopting Dr. Grofman's terminology, see
Tr. 195, the court found that in all but 2 of the 53 elections*fn23 the degree of racial bloc voting was "so marked as to be substantively significant, in the sense that the results of the individual election would have been different depending upon whether it had been held among only the white voters or only the black voters." 590 F.Supp., at 368.
The court also reported its findings, both in tabulated numerical form and in written form, that a high percentage of black voters regularly supported black candidates and that most white voters were extremely reluctant to vote for black candidates. The court then considered the relevance to the existence of legally significant white bloc voting of the fact that black candidates have won some elections. It determined that in most instances, special circumstances, such as incumbency and lack of opposition, rather than a diminution in usually severe white bloc voting, accounted for these candidates' success. The court also suggested that black voters' reliance on bullet voting was a significant factor in their successful efforts to elect candidates of their choice. Based on all of the evidence before it, the trial court concluded that each of the districts experienced racially polarized voting "in a persistent and severe degree." Id., at 367.
THE DEGREE OF BLOC VOTING THAT IS LEGALLY SIGNIFICANT UNDER § 2
North Carolina and the United States argue that the test used by the District Court to determine whether voting patterns in the disputed districts are racially polarized to an extent cognizable under § 2 will lead to results that are inconsistent with congressional intent. North Carolina maintains
that the court considered legally significant racially polarized voting to occur whenever "less than 50% of the white voters cast a ballot for the black candidate." Brief for Appellants 36. Appellants also argue that racially polarized voting is legally significant only when it always results in the defeat of black candidates. Id., at 39-40.
The United States, on the other hand, isolates a single line in the court's opinion and identifies it as the court's complete test. According to the United States, the District Court adopted a standard under which legally significant racial bloc voting is deemed to exist whenever "'the results of the individual election would have been different depending upon whether it had been held among only the white voters or only the black voters in the election.'" Brief for United States as Amicus Curiae 29 (quoting 590 F.Supp., at 368). We read the District Court opinion differently.
The Standard for Legally Significant Racial Bloc Voting
The Senate Report states that the "extent to which voting in the elections of the state or political subdivision is racially polarized," S. Rep., at 29, is relevant to a vote dilution claim. Further, courts and commentators agree that racial bloc voting is a key element of a vote dilution claim. See, e. g., Escambia County, Fla., 748 F.2d, at 1043; United States v. Marengo County Comm'n, 731 F.2d 1546, 1566 (CA11), appeal dism'd and cert. denied, 469 U.S. 976 (1984); Nevett v. Sides, 571 F.2d 209, 223 (CA5 1978), cert. denied, 446 U.S. 951 (1980); Johnson v. Halifax County, 594 F.Supp. 161, 170 (EDNC 1984); Blacksher & Menefee; Engstrom & Wildgen, 465, 469; Parker 107; Note, Geometry and Geography 199. Because, as we explain below, the extent of bloc voting necessary to demonstrate that a minority's ability to elect its preferred representatives is impaired varies according to several factual circumstances, the degree of bloc voting which constitutes the threshold of legal significance will vary
from district to district. Nonetheless, it is possible to state some general principles and we proceed to do so.
The purpose of inquiring into the existence of racially polarized voting is twofold: to ascertain whether minority group members constitute a politically cohesive unit and to determine whether whites vote sufficiently as a bloc usually to defeat the minority's preferred candidates. See supra, at 48-51. Thus, the question whether a given district experiences legally significant racially polarized voting requires discrete inquiries into minority and white voting practices. A showing that a significant number of minority group members usually vote for the same candidates is one way of proving the political cohesiveness necessary to a vote dilution claim, Blacksher & Menefee 59-60, and n. 344, and, consequently, establishes minority bloc voting within the context of § 2. And, in general, a white bloc vote that normally will defeat the combined strength of minority support plus white "crossover" votes rises to the level of legally significant white bloc voting. Id., at 60. The amount of white bloc voting that can generally "minimize or cancel," S. Rep., at 28; Regester, 412 U.S., at 765, black voters' ability to elect representatives of their choice, however, will vary from district to district according to a number of factors, including the nature of the allegedly dilutive electoral mechanism; the presence or absence of other potentially dilutive electoral devices, such as majority vote requirements, designated posts, and prohibitions against bullet voting; the percentage of registered voters in the district who are members of the minority group; the size of the district; and, in multimember districts, the number of seats open and the number of candidates in the field.*fn24 See, e. g ., Butler 874-876; Davidson 5; Jones, The Impact of Local Election Systems on Black Political Representation, 11 Urb. Aff. Q. 345 (1976); United States Commission
on Civil Rights, The Voting Rights Act: Unfulfilled Goals 38-41 (1981).
Because loss of political power through vote dilution is distinct from the mere inability to win a particular election, Whitcomb, 403 U.S., at 153, a pattern of racial bloc voting that extends over a period of time is more probative of a claim that a district experiences legally significant polarization than are the results of a single election.*fn25 Blacksher & Menefee 61; Note, Geometry and Geography 200, n. 66 ("Racial polarization should be seen as an attribute not of a single election, but rather of a polity viewed over time. The concern is necessarily temporal and the analysis historical because the evil to be avoided is the subordination of minority groups in American politics, not the defeat of individuals in particular electoral contests"). Also for this reason, in a district where elections are shown usually to be polarized, the fact that racially polarized voting is not present in one or a few individual elections does not necessarily negate the conclusion that the district experiences legally significant bloc voting. Furthermore, the success of a minority candidate in a particular election does not necessarily prove that the district did not experience polarized voting in that election; special circumstances, such as the absence of an opponent, incumbency, or the utilization of bullet voting, may explain minority electoral success in a polarized contest.*fn26
As must be apparent, the degree of racial bloc voting that is cognizable as an element of a § 2 vote dilution claim will
vary according to a variety of factual circumstances. Consequently, there is no simple doctrinal test for the existence of legally significant racial bloc voting. However, the foregoing general principles should provide courts with substantial guidance in determining whether evidence that black and white voters generally prefer different candidates rises to the level of legal significance under § 2.
Standard Utilized by the District Court
The District Court clearly did not employ the simplistic standard identified by North Carolina -- legally significant bloc voting occurs whenever less than 50% of the white voters cast a ballot for the black candidate. Brief for Appellants 36. And, although the District Court did utilize the measure of "substantive significance" that the United States ascribes to it -- "'the results of the individual election would have been different depending on whether it had been held among only the white voters or only the black voters,'" Brief for United States as Amicus Curiae 29 (quoting 590 F.Supp., at 368) -- the court did not reach its ultimate conclusion that the degree of racial bloc voting present in each district is legally significant through mechanical reliance on this standard.*fn27 While the court did not phrase the standard for legally significant racial bloc voting exactly as we do, a fair reading of the court's opinion reveals that the court's analysis conforms to our view of the proper legal standard.
The District Court's findings concerning black support for black candidates in the five multimember districts at issue
here clearly establish the political cohesiveness of black voters. As is apparent from the District Court's tabulated findings, reproduced in Appendix A to opinion, post, p. 80, black voters' support for black candidates was overwhelming in almost every election. In all but 5 of 16 primary elections, black support for black candidates ranged between 71% and 92%; and in the general elections, black support for black Democratic candidates ranged between 87% and 96%.
In sharp contrast to its findings of strong black support for black candidates, the District Court found that a substantial majority of white voters would rarely, if ever, vote for a black candidate. In the primary elections, white support for black candidates ranged between 8% and 50%, and in the general elections it ranged between 28% and 49%. See ibid. The court also determined that, on average, 81.7% of white voters did not vote for any black candidate in the primary elections. In the general elections, white voters almost always ranked black candidates either last or next to last in the multicandidate field, except in heavily Democratic areas where white voters consistently ranked black candidates last among the Democrats, if not last or next to last among all candidates. The court further observed that approximately two-thirds of white voters did not vote for black candidates in general elections, even after the candidate had won the Democratic primary and the choice was to vote for a Republican or for no one.*fn28
While the District Court did not state expressly that the percentage of whites who refused to vote for black candidates in the contested districts would, in the usual course of events, result in the defeat of the minority's candidates, that conclusion is apparent both from the court's factual findings and from the rest of its analysis. First, with the exception of House District 23, see infra, at 77, the trial court's findings clearly show that black voters have enjoyed only minimal and sporadic success in electing representatives of their choice. See Appendix B to opinion, post, p. 82. Second, where black candidates won elections, the court closely examined the circumstances of those elections before concluding that the success of these blacks did not negate other evidence, derived from all of the elections studied in each district, that legally significant ...