Justice Powell
announced the judgment of the Court and delivered an opinion in which The Chief Justice and Justice Rehnquist join, and in all but Part IV of which Justice O’Connor joins.
This case presents the question whether a school board, consistent with the Equal Protection Clause, may extend preferential protection against layoffs to some of its employees because of their race or national origin.
I
In 1972 the Jackson Board of Education, because of racial tension in the community that extended to its schools, considered adding a layoff provision to the Collective Bargaining Agreement (CBA) between the Board and the Jackson Education Association (Union) that would protect employees who were members of certain minority groups against layoffs. The Board and the Union eventually approved a new provision, Article XII of the CBA, covering layoffs. It stated:
“In the event that it becomes necessary to reduce the number of teachers through layoff from employment by the Board, teachers with the most seniority in the district shall be retained, except that at no time will there be a greater percentage of minority personnel laid off than the current percentage of minority personnel employed at the time of the layoff. In no event will the number given notice of possible layoff be greater than the number of positions to be eliminated. Each teacher so affected will be called back in reverse order for positions for which he is certificated maintaining the above minority balance.” App. 13.
When layoffs became necessary in 1974, it was evident that adherence to the CBA would result in the layoff of tenured nonminority teachers while minority teachers on probationary status were retained. Rather than complying with Article XII, the Board retained the tenured teachers and laid off probationary minority teachers, thus failing to maintain the percentage of minority personnel that existed at the time of the layoff. The Union, together with two minority teachers who had been laid off, brought suit in federal court, id., at 30 (Jackson Education Assn. v. Board of Education (Jackson I) (mem. op.)), claiming that the Board’s failure to adhere to the layoff provision violated the Equal Protection Clause of the Fourteenth Amendment and Title VII of the Civil Rights Act of 1964. They also urged the District Court to take pendent jurisdiction over state-law contract claims., In its answer the Board denied any prior employment discrimination and argued that the layoff provision conflicted with the Michigan Teacher Tenure Act. App. 33. Following trial, the District Court sua sponte concluded that it lacked jurisdiction over the case, in part because there was insufficient evidence to support the plaintiffs’ claim that the Board had engaged in discriminatory hiring practices prior to 1972, id., at 35-37, and in part because the plaintiffs had not fulfilled the jurisdictional prerequisite to a Title VII claim by filing discrimination charges with the Equal Employment Opportunity Commission. After dismissing the federal claims, the District Court declined to exercise pendent jurisdiction over the state-law contract claims.
Rather than taking an appeal, the plaintiffs instituted a suit in state court, Jackson Education Assn. v. Board of Education, No. 77-011484CZ (Jackson Cty. Cir. Ct. 1979) (Jackson II), raising in essence the same claims that had been raised in Jackson I. In entering judgment for the plaintiffs, the state court found that the Board had breached its contract with the plaintiffs, and that Article XII did not violate the Michigan Teacher Tenure Act. In rejecting the Board’s argument that the layoff provision violated the Civil Rights Act of 1964, the state court found that it “ha[d] not been established that the board had discriminated against minorities in its hiring practices. The minority representation on the faculty was the result of societal racial discrimination.” App. 43. The state court also found that “[tjhere is no history of overt past discrimination by the parties to this contract.” Id., at 49. Nevertheless, the court held that Article XII was permissible, despite its discriminatory effect on non-minority teachers, as an attempt to remedy the effects of societal discrimination.
After Jackson II, the Board adhered to Article XII. As a result, during the 1976-1977 and 1981-1982 school years, nonminority teachers were laid off, while minority teachers with less seniority were retained. The displaced nonminority teachers, petitioners here, brought suit in Federal District Court, alleging violations of the Equal Protection Clause, Title VII, 42 U. S. C. § 1983, and other federal and state statutes. On cross-motions for summary judgment, the District Court dismissed all of petitioners’ claims. 546 F. Supp. 1195 (ED Mich. 1982). With respect to the equal protection claim, the District Court held that the racial preferences granted by the Board need not be grounded on a finding of prior discrimination. Instead, the court decided that the racial preferences were permissible under the Equal Protection Clause as an attempt to remedy societal discrimination by providing “role models” for minority schoolchildren, and upheld the constitutionality of the layoff provision.
The Court of Appeals for the Sixth Circuit affirmed, largely adopting the reasoning and language of the District Court. 746 F. 2d 1152 (1984). We granted certiorari, 471 U. S. 1014 (1985), to resolve the important issue of the constitutionality of race-based layoffs by public employers. We now reverse.
II
Petitioners’ central claim is that they were laid off because of their race in violation of the Equal Protection Clause of the Fourteenth Amendment. Decisions by faculties and administrators of public schools based on race or ethnic origin are reviewable under the Fourteenth Amendment. This Court has “consistently repudiated ‘[distinctions between citizens solely because of their ancestry’ as being ‘odious to a free people whose institutions are founded upon the doctrine of equality,’” Loving v. Virginia, 388 U. S. 1, 11 (1967), quoting Hirabayashi v. United States, 320 U. S. 81, 100 (1943). “Racial and ethnic distinctions of any sort are inherently suspect and thus call for the most exacting judicial examination.” University of California Regents v. Bakke, 438 U. S. 265, 291 (1978) (opinion of Powell, J., joined by White, J.).
The Court has recognized that the level of scrutiny does not change merely because the challenged classification operates against a group that historically has not been subject to governmental discrimination. Mississippi University for Women v. Hogan, 458 U. S. 718, 724, n. 9 (1982); Bakke, supra, at 291-299; see Shelley v. Kraemer, 334 U. S. 1, 22 (1948); see also A. Bickel, The Morality of Consent 133 (1975). In this case, Article XII of the CBA operates against whites and in favor of certain minorities, and therefore constitutes a classification based on race. “Any preference based on racial or ethnic criteria must necessarily receive a most searching examination to make sure that it does not conflict with constitutional guarantees.” Fullilove v. Klutznick, 448 U. S. 448, 491 (1980) (opinion of Burger, C. J.). There are two prongs to this examination. First, any racial classification “must be justified by a compelling governmental interest.” Palmore v. Sidoti, 466 U. S. 429, 432 (1984); see Loving v. Virginia, supra, at 11; cf. Graham v. Richardson, 403 U. S. 365, 375 (1971) (alienage). Second, the means chosen by the State to effectuate its purpose must be “narrowly tailored to the achievement of that goal.” Fullilove, supra, at 480. We must decide whether the layoff provision is supported by a compelling state purpose and whether the means chosen to accomplish that purpose are narrowly tailored.
Ill
A
The Court of Appeals, relying on the reasoning and language of the District Court’s opinion, held that the Board’s interest in providing minority role models for its minority students, as an attempt to alleviate the effects of societal discrimination, was sufficiently important to justify the racial classification embodied in the layoff provision. 746 F. 2d, at 1156-1157. The court discerned a need for more minority faculty role models by finding that the percentage of minority teachers was less than the percentage of minority students. Id., at 1156.
This Court never has held that societal discrimination alone is sufficient to justify a racial classification. Rather, the Court has insisted upon some showing of prior discrimination by the governmental unit involved before allowing limited use of racial classifications in order to remedy such discrimination. This Court’s reasoning in Hazelwood School District v. United States, 433 U. S. 299 (1977), illustrates that the relevant analysis in cases involving proof of discrimination by statistical disparity focuses on those disparities that demonstrate such prior governmental discrimination. In Hazelwood the Court concluded that, absent employment discrimination by the school board, “ ‘nondiscriminatory hiring practices will in time result in a work force more or less representative of the racial and ethnic composition of the population in the community from which employees are hired.’” Id., at 307, quoting Teamsters v. United States, 431 U. S. 324, 340, n. 20 (1977). See also 746 F. 2d, at 1160 (Wellford, J., concurring) (“Had the plaintiffs in this case presented data as to the percentage of qualified minority teachers in the relevant labor market to show that defendant Board’s hiring of black teachers over a number of years had equalled that figure, I believe this court may well have been required to reverse . . .”). Based on that reasoning, the Court in Hazelwood held that the proper comparison for determining the existence of actual discrimination by the school board was “between the racial composition of [the school’s] teaching staff and the racial composition of the qualified public school teacher population in the relevant labor market.” 433 U. S., at 308. Hazelwood demonstrates this Court’s focus on prior discrimination as the justification for, and the limitation on, a State’s adoption of race-based remedies. See also Swann v. Charlotte-Mecklenburg Board of Education, 402 U. S. 1 (1971).
Unlike the analysis in Hazelwood, the role model theory employed by the District Court has no logical stopping point. The role model theory allows the Board to engage in discriminatory hiring and layoff practices long past the point required by any legitimate remedial purpose. Indeed, by tying the required percentage of minority teachers to the percentage of minority students, it requires just the sort of year-to-year calibration the Court stated was unnecessary in Swann, 402 U. S., at 31-32:
“At some point these school authorities and others like them should have achieved full compliance with this Court’s decision in Brown I. . . . Neither school authorities nor district courts are constitutionally required to make year-by-year adjustments of the racial composition of student bodies once the affirmative duty to desegregate has been accomplished and racial discrimination through official action is eliminated from the system.”
See also id., at 24.
Moreover, because the role model theory does not necessarily bear a relationship to the harm caused by prior discriminatory hiring practices, it actually could be used to escape the obligation to remedy such practices by justifying the small percentage of black teachers by reference to the small percentage of black students. See United States v. Hazelwood School District, 392 F. Supp. 1276, 1286-1287 (ED Mo. 1975), rev’d, 534 F. 2d 805 (CA8 1976), rev’d and remanded, 433 U. S. 299 (1977). Carried to its logical extreme, the idea that black students are better off with black teachers could lead to the very system the Court rejected in Brown v. Board of Education, 347 U. S. 483 (1954) (Brown I).
Societal discrimination, without more, is too amorphous a basis for imposing a racially classified remedy. The role model theory announced by the District Court and the resultant holding typify this indefiniteness. There are numerous explanations for a disparity between the percentage of minority students and the percentage of minority faculty, many of them completely unrelated to discrimination of any kind. In fact, there is no apparent connection between the two groups. Nevertheless, the District Court combined irrelevant comparisons between these two groups with an indisputable statement that there has been societal discrimination, and upheld state action predicated upon racial classifications. No one doubts that there has been serious racial discrimination in this country. But as the basis for imposing discriminatory legal remedies that work against innocent people, societal discrimination is insufficient and over-expansive. In the absence of particularized findings, a court could uphold remedies that are ageless in their reach into the past, and timeless in their ability to affect the future.
B
Respondents also now argue that their purpose in adopting the layoff provision was to remedy prior discrimination against minorities by the Jackson School District in hiring teachers. Public schools, like other public employers, operate under two interrelated constitutional duties. They are under a clear command from this Court, starting with Brown v. Board of Education, 349 U. S. 294 (1955), to eliminate every vestige of racial segregation and discrimination in the schools. Pursuant to that goal, race-conscious remedial action may be necessary. North Carolina State Board of Education v. Swann, 402 U. S. 43, 46 (1971). On the other hand, public employers, including public schools, also must act in accordance with a “core purpose of the Fourteenth Amendment” which is to “do away with all govemmentally imposed discriminations based on race.” Palmore v. Sidoti, 466 U. S., at 432. These related constitutional duties are not always harmonious; reconciling them requires public employers to act with extraordinary care. In particular, a public employer like the Board must ensure that, before it embarks on an affirmative-action program, it has convincing evidence that remedial action is warranted. That is, it must have sufficient evidence to justify the conclusion that there has been prior discrimination.
Evidentiary support for the conclusion that remedial action is warranted becomes crucial when the remedial program is challenged in court by nonminority employees. In this case, for example, petitioners contended at trial that the remedial program — Article XII — had the purpose and effect of instituting a racial classification that was not justified by a remedial purpose. 546 F. Supp., at 1199. In such a case, the trial court must make a factual determination that the employer had a strong basis in evidence for its conclusion that remedial action was necessary. The ultimate burden remains with the employees to demonstrate the unconstitutionality of an affirmative-action program. But unless such a determination is made, an appellate court reviewing a challenge by nonminority employees to remedial action cannot determine whether the race-based action is justified as a remedy for prior discrimination.
Despite the fact that Article XII has spawned years of litigation and three separate lawsuits, no such determination ever has been made. Although its litigation position was different, the Board in Jackson I and Jackson II denied the existence of prior discriminatory hiring practices. App. 33. This precise issue was litigated in both those suits. Both courts concluded that any statistical disparities were the result of general societal discrimination, not of prior discrimination by the Board. The Board now contends that, given another opportunity, it could establish the existence of prior discrimination. Although this argument seems belated at this point in the proceedings, we need not consider the question since we conclude below that the layoff provision was not a legally appropriate means of achieving even a compelling purpose.
IV
The Court of Appeals examined the means chosen to accomplish the Board’s race-conscious purposes under a test of “reasonableness.” That standard has no support in the decisions of this Court. As demonstrated in Part II above, our decisions always have employed a more stringent standard — however articulated — to test the validity of the means chosen by a State to accomplish its race-conscious purposes. See, e. g., Palmore, supra, at 432 (“[T]o pass constitutional muster, [racial classifications] must be ‘necessary ... to the accomplishment’ of their legitimate purpose”) (quoting McLaughlin v. Florida, 379 U. S. 184, 196 (1964)); Fullilove, 448 U. S., at 480 (opinion of Burger, C. J.) (“We recognize the need for careful judicial evaluation to assure that any . . . program that employs racial or ethnic criteria to accomplish the objective of remedying the present effects of past discrimination is narrowly tailored to the achievement of that goal”)- Under strict scrutiny the means chosen to accomplish the State’s asserted purpose must be specifically and narrowly framed to accomplish that purpose. Fullilove, 448 U. S., at 480 (opinion of Burger, C. J.). “Racial classifications are simply too pernicious to permit any but the most exact connection between justification and classification.” Id., at 537 (Stevens, J., dissenting).
We have recognized, however, that in order to remedy the effects of prior discrimination, it may be necessary to take race into account. As part of this Nation’s dedication to eradicating racial discrimination, innocent persons may be called upon to bear some of the burden of the remedy. “When effectuating a limited and properly tailored remedy to cure the effects of prior discrimination, such a ‘sharing of the burden’ by innocent parties is not impermissible.” Id., at 484, quoting Franks v. Bowman Transportation Co., 424 U. S. 747, 777 (1976). In Fullilove, the challenged statute required at least 10 percent of federal public works funds to be used in contracts with minority-owned business enterprises. This requirement was found to be within the remedial powers of Congress in part because the “actual ‘burden’ shouldered by nonminority firms is relatively light.” 448 U. S., at 484.
Significantly, none of the cases discussed above involved layoffs. Here, by contrast, the means chosen to achieve the Board’s asserted purposes is that of laying off nonminority teachers with greater seniority in order to retain minority teachers with less seniority. We have previously expressed concern over the burden that a preferential-layoffs scheme imposes on innocent parties. See Firefighters v. Stotts, 467 U. S. 561, 574-576, 578-579 (1984); see also Steelworkers v. Weber, 443 U. S. 193, 208 (1979) (“The plan does not require the discharge of white workers and their replacement with new black hirees”). In cases involving valid hiring goals, the burden to be borne by innocent individuals is diffused to a considerable extent among society generally. Though hiring goals may burden some innocent individuals, they simply do not impose the same kind of injury that layoffs impose. Denial of a future employment opportunity is not as intrusive as loss of an existing job.
Many of our cases involve union seniority plans with employees who are typically heavily dependent on wages for their day-to-day living. Even a temporary layoff may have adverse financial as well as psychological effects. A worker may invest many productive years in one job and one city with the expectation of earning the stability and security of seniority. “At that point,' the rights and expectations surrounding seniority make up what is probably the most valuable capital asset that the worker ‘owns,’ worth even more than the current equity in his home.” Fallon & Weiler, Conflicting Models of Racial Justice, 1984 S. Ct. Rev. 1, 58. Layoffs disrupt these settled expectations in a way that general hiring goals do not.
While hiring goals impose a diffuse burden, often foreclosing only one of several opportunities, layoffs impose the entire burden of achieving racial equality on particular individuals, often resulting in serious disruption of their lives. That burden is too intrusive. We therefore hold that, as a means of accomplishing purposes that otherwise may be legitimate, the Board’s layoff plan is not sufficiently narrowly tailored. Other, less intrusive means of accomplishing similar purposes — such as the adoption of hiring goals — are available. For these reasons, the Board’s selection of layoffs as the means to accomplish even a valid purpose cannot satisfy the demands of the Equal Protection Clause.
V
We accordingly reverse the judgment of the Court of Appeals for the Sixth Circuit.
It is so ordered.
Prior to bargaining on this subject, the Minority Affairs Office of the Jackson Public Schools sent a questionnaire to all teachers, soliciting their views as to a layoff policy. The questionnaire proposed two alternatives: continuation of the existing straight seniority system, or a freeze of minority layoffs to ensure retention of minority teachers in exact proportion to the minority student population. Ninety-six percent of the teachers who responded to the questionnaire expressed a preference for the straight seniority system.
Article VII of the CBA defined “minority group personnel” as “those employees who are Black, American Indian, Oriental, or of Spanish descendancy.” App. 15.
Petitioners have sought review in this Court only of their claim based on the Equal Protection Clause.
School district collective-bargaining agreements constitute state action for purposes of the Fourteenth Amendment. Abood v. Detroit Board of Ed., 431 U. S. 209, 218, and n. 12 (1977).
Justice Marshall contends that “the plurality has too quickly assumed the absence of a legitimate factual predicate ... for affirmative action in the Jackson schools,” post, at 297. In support of that assertion, he engages in an unprecedented reliance on nonrecord documents that respondent has “lodged” with this Court. This selective citation to factual materials not considered by the District Court or the Court of Appeals below is unusual enough by itself. My disagreement with Justice Marshall, however, is more fundamental than any disagreement over the heretofore unquestioned rule that this Court decides eases based on the record before it. Justice Marshall does not define what he means by “legitimate factual predicate,” nor does he demonstrate the relationship of these nonrecord materials to his undefined predicate. If, for example, his dissent assumes that general societal discrimination is a sufficient factual predicate, then there is no need to refer to respondents’ lodgings as to its own employment history. No one disputes that there has been race discrimination in this country. If that fact alone can justify race-conscious action by the State, despite the Equal Protection Clause, then the dissent need not rely on nonrecord materials to show a “legitimate factual predicate.” If, on the other hand, Justice Marshall is assuming that the necessary factual predicate is prior discrimination by the Board, there is no escaping the need for a factual determination below — a determination that does not exist.
The real dispute, then, is not over the state of the record. It is disagreement as to what constitutes a “legitimate factual predicate.” If the necessary factual predicate is prior discrimination — that is, that race-based state action is taken to remedy prior discrimination by the governmental unit involved — then the very nature of appellate review requires that a factfinder determine whether the employer was justified in instituting a remedial plan. Nor can respondents unilaterally insulate themselves from this key constitutional question by conceding that they have discriminated in the past, now that it is in their interest to make such a concession. Contrary to the dissent’s assertion, the requirement of such a determination by the trial court is not some arbitrary barrier set up by today’s opinion. Rather, it is a necessary result of the requirement that race-based state action be remedial.
At any rate, much of the material relied on by Justice Marshall has been the subject of the previous lawsuit in Jackson II, where the court concluded that it “had not been established that the board had discriminated against minorities in its hiring practices.” App. 43. Moreover, as noted supra, at 271, in Jackson I the Board expressly denied that it had engaged in employment discrimination.
The term “narrowly tailored,” so frequently used in our cases, has acquired a secondary meaning. More specifically, as commentators have indicated, the term may be used to require consideration of whether lawful alternative and less restrictive means could have been used. Or, as Professor Ely has noted, the classification at issue must “fit” with greater precision than any alternative means. Ely, The Constitutionality of Reverse Racial Discrimination, 41 U. Chi. L. Rev. 723, 727, n. 26 (1974). “[Courts] should give particularly intense scrutiny to whether a nonracial approach or a more narrowly-tailored racial classification could promote the substantial interest about as well and at tolerable administrative expense.” Greenawalt, Judicial Scrutiny of “Benign” Racial Preference in Law School Admissions, 75 Colum. L. Rev. 559, 578-579 (1975).
Several commentators have emphasized that, no matter what the weight of the asserted governmental purpose, the means chosen to accomplish the purpose should be narrowly tailored. In arguing for a form of intermediate scrutiny, Professor Greenawalt contends that, “while benign racial classifications call for some weighing of the importance of ends they call for even more intense scrutiny of means, especially of the administrability of less onerous alternative classifications.” Greenawalt, supra, at 565. Professor Ely has suggested that “special scrutiny in the suspect classification context has in fact consisted not in weighing ends but rather in insisting that the classification in issue fit a constitutionally permissible state goal with greater precision than any available alternative.” Ely, supra, at 727, n. 26. Professor Gunther argues that judicial scrutiny of legislative means is more appropriate than judicial weighing of the importance of the legislative purpose. Gunther, The Supreme Court, 1971 Term — Foreword: In Search of Evolving Doctrine on a Changing Court: A Model For a Newer Equal Protection, 86 Harv. L. Rev. 1, 20-21 (1972).
Of course, when a State implements a race-based plan that requires such a sharing of the burden, it cannot justify the discriminatory effect on some individuals because other individuals had approved the plan. Any “waiver” of the right not to be dealt with by the government on the basis of one’s race must be made by those affected. Yet Justice Marshall repeatedly contends that the fact that Article XII was approved by a majority vote of the Union somehow validates this plan. He sees this ease not in terms of individual constitutional rights, but as an allocation of burdens “between two racial groups.” Post, at 309. Thus, Article XII becomes a political compromise that “avoided placing the entire burden of layoffs on either the white teachers as a group or the minority teachers as a group.” Post, at 299. But the petitioners before us today are not “the white teachers as a group.” They are Wendy Wygant and other individuals who claim that they were fired from their jobs because of their race. That claim cannot be waived by petitioners’ more senior colleagues. In view of the way union seniority works, it is not surprising that while a straight freeze on minority layoffs was overwhelmingly rejected, a “compromise” eventually was reached that placed the entire burden of the compromise on the most junior union members. The more senior union members simply had nothing to lose from such a compromise. See ibid. (“To petitioners, at the bottom of the seniority scale among white teachers, fell the lot of bearing the white group’s proportionate share of layoffs that became necessary in 1982.”) The fact that such a painless accommodation was approved by the more senior union members six times since 1972 is irrelevant. The Constitution does not allocate constitutional rights to be distributed like bloc grants within discrete racial groups; and until it does, petitioners’ more senior union colleagues cannot vote away petitioners’ rights.
Justice Marshall also attempts to portray the layoff plan as one that has no real invidious effect, stating that “within the confines of constant minority proportions, it preserves the hierarchy of seniority in the selection of individuals for layoff.” Post, at 309. That phrase merely expresses the tautology that layoffs are based on seniority except as to those nonminority teachers who are displaced by minority teachers with less seniority. This is really nothing more than group-based analysis: “[E]ach group would shoulder a portion of [the layoff] burden equal to its portion of the faculty.” Post, at 299. The constitutional problem remains: the decision that petitioners would be laid off was based on their race.
Similarly, the Court approved the hiring program in Steelworkers v. Weber, 443 U. S. 193, 208 (1979), in part because the plan did not “unnecessarily trammel the interests of the white employees.” Since Weber involved a private company, its reasoning concerning the validity of the hiring plan at issue there is not directly relevant to this case, which involves a state-imposed plan. No equal protection claim was presented in Weber.
There are cases involving alteration of strict seniority layoffs, see, e. g., Ford Motor Co. v. Huffman, 345 U. S. 330 (1953); Aeronautical Industrial District Lodge 727 v. Campbell, 337 U. S. 521 (1949), but they do not involve the critical element here — layoffs based on race. The Constitution does not require layoffs to be based on strict seniority. But it does require the State to meet a heavy burden of justification when it implements a layoff plan based on race.
The “school admission” cases, which involve the same basic concepts as cases involving hiring goals, illustrate this principle. For example, in DeFunis v. Odegaard, 416 U. S. 312 (1974), while petitioner’s complaint alleged that he had been denied admission to the University of Washington Law School because of his race, he also had been accepted at the Oregon, Idaho, Gonzaga, and Willamette Law Schools. DeFunis v. Odegaard, 82 Wash. 2d 11, 30, n. 11, 507 P. 2d 1169, 1181, n. 11 (1973). The injury to DeFunis was not of the same kind or degree as the injury that he would have suffered had he been removed from law school in his third year. Even this analogy may not rise to the level of harm suffered by a union member who is laid off.
We have recognized, however, that in order to provide make-whole relief to the actual, identified victims of individual discrimination, a court may in an appropriate ease award competitive seniority. See Franks v. Bowman Transportation Co., 424 U. S. 747 (1976).
The Board’s definition of minority to include blacks, Orientals, American Indians, and persons of Spanish descent, n. 2, supra, further illustrates the undifferentiated nature of the plan. There is no explanation of why the Board chose to favor these particular minorities or how in fact members of some of the categories can be identified. Moreover, respondents have never suggested — much less formally found — that they have engaged in prior, purposeful discrimination against members of each of these minority groups.