with respect to these northeast Denver schools show an undeviating purpose to isolate Negro students” in segregated schools "while preserving the Anglo character of [other] schools." 303 F. Supp., at 294. This finding did not relate to an insubstantial or trivial fragment of the school system. On the contrary, respondent School Board was found guilty of following a deliberate segregation policy at schools attended, in 1969, by 37.69% of Denver's total Negro school population, including one-fourth of the Negro elementary pupils, over two-thirds of the Negro junior high pupils, and over two-fifths of the Negro high school pupils." In addition,

10 The Board was found guilty of intentionally segregative acts of one kind or another with respect to the schools listed below. (As to Cole and East, the conclusion rests on the rescission of the resolutions.) PUPILS 1968-1969

Thus, the above-mentioned schools included:

Elementary 25.36% of all Negro elementary pupils
Junior High 68.99% of all Negro junior high pupils
Senior High 42.55% of all Negro senior high pupils
Total 37.69% of all Negro pupils

there was uncontroverted evidence that teachers and staff had for years been assigned on the basis of a minority teacher to a minority school throughout the school system. Respondent argues, however, that a finding of stateimposed segregation as to a substantial portion of the school system can be viewed in isolation from the rest of the district, and that even if state-imposed segregation does exist in a substantial part of the Denver school system, it does not follow that the District Court could predicate on that fact a finding that the entire school system is a dual system. We do not agree. We have never suggested that plaintiffs in school desegregation cases must bear the burden of proving the elements of de jure segregation as to each and every school or each and every student within the school system. Rather, we have held that where plaintiffs prove that a current condition of segregated schooling exists within a school district where a dual system was compelled or authorized by statute at the time of our decision in Brown v. Board of Education, 347 U. S. 483 (1954) (Brown I), the State automatically assumes an affirmative duty "to effectuate a transition to a racially nondiscriminatory school system," Brown v. Board of Education, 349 U. S. 294, 301 (1955) (Brown II), see also Green v. County School Board, 391 U. S. 430, 437-438 (1968), that is, to eliminate from the public schools within their school system "all vestiges of state-imposed segregation." Swann v. Charlotte-Mecklenburg Boud of Education, 402 U. S. 1, 15 (1971).11

11 Our Brother REHNQUIST argues in dissent that Brown v. Board of Education did not impose an "affirmative duty to integrate" the schools of a dual school system but was only a "prohibition against discrimination" "in the sense that the assignment of a child to a particular school is not made to depend on his race . . ." Infra, at 258. That is the interpretation of Brown expressed 18 years ago by a three-judge court in Briggs v. Elliott, 132 F. Supp. 776, 777

189

Opinion of the Court.

This is not a case, however, where a statutory dual system has ever existed. Nevertheless, where plaintiffs prove that the school authorities have carried out a systematic program of segregation affecting a substantial portion of the students, schools, teachers, and facilities within the school system, it is only common sense to conclude that there exists a predicate for a finding of the existence of a dual school system. Several considerations support this conclusion. First, it is obvious that a practice of concentrating Negroes in certain schools by structuring attendance zones or designating "feeder" schools on the basis of race has the reciprocal effect of keeping other nearby schools predominantly white. Similarly, the practice of building a school-such as the Barrett Elementary School in this case-to a certain size and in a certain location, "with conscious knowledge that it would

12

(1955): "The Constitution, in other words, does not require integration. It merely forbids discrimination." But Green v. County School Board, 391 U. S. 430, 437-438 (1968), rejected that interpretation insofar as Green expressly held that "School boards... operating state-compelled dual systems were nevertheless clearly charged [by Brown II] with the affirmative duty to take whatever steps might be necessary to convert to a unitary system in which racial discrimination would be eliminated root and branch." Green remains the governing principle. Alexander v. Holmes County Board of Education, 396 U. S. 19 (1969); Swann v. Charlotte-Mecklenburg Board of Education, 402 U. S. 1, 15 (1971). See also Kelley v. Metropolitan County Board of Education, 317 F. Supp. 980, 984 (1970).

12 As a former School Board President who testified for the respondents put it: "Once you change the boundary of any one school, it is affecting all the schools . . . ." Testimony of Mrs. Lois Heath Johnson on cross-examination. App. 951a-952a.

Similarly, Judge Wisdom has recently stated:

"Infection at one school infects all schools. To take the most sinple example, in a two school system, all blacks at one school mears all or almost all whites at the other." United States v. Texas Eaucation Agency, 467 F. 2d 848, 888 (CA5 1972).

Opinion of the Court

413 U.S. be a segregated school," 303 F. Supp., at 285, has a substantial reciprocal effect on the racial composition of other nearby schools. So also, the use of mobile classrooms, the drafting of student transfer policies, the transportation of students, and the assignment of faculty and staff, on racially identifiable bases, have the clear effect of earmarking schools according to their racial composition, and this, in turn, together with the elements of student assignment and school construction, may have a profound reciprocal effect on the racial composition of residential neighborhoods within a metropolitan area, thereby causing further racial concentration within the schools. We recognized this in Swann when we said:

"They [school authorities] must decide questions of location and capacity in light of population growth, finances, land values, site availability, through an almost endless list of factors to be considered. The result of this will be a decision which, when combined with one technique or another of student assignment, will determine the racial composition of the student body in each school in the system. Over the long run, the consequences of the choices will be far reaching. People gravitate toward school facilities, just as schools are located in response to the needs of people. The location of schools may thus influence the patterns of residential development of a metropolitan area and have important impact on composition of inner-city neighborhoods.

"In the past, choices in this respect have been used as a potent weapon for creating or maintaining a state-segregated school system. In addition to the classic pattern of building schools specifically intended for Negro or white students, school authorities have sometimes, since Brown, closed schools

which appeared likely to become racially mixed through changes in neighborhood residential patterns. This was sometimes accompanied by building new schools in the areas of white suburban expansion farthest from Negro population centers in order to maintain the separation of the races with a minimum departure from the formal principles of 'neighborhood zoning.' Such a policy does more than simply influence the short-run composition of the student body of a new school. It may well promote segregated residential patterns which, when combined with 'neighborhood zoning,' further lock the school system into the mold of separation of the races. Upon a proper showing a district court may consider this in fashioning a remedy." 402 U. S., at 20-21.

In short, common sense dictates the conclusion that racially inspired school board actions have an impact beyond the particular schools that are the subjects of those actions. This is not to say, of course, that there can never be a case in which the geographical structure of, or the natural boundaries within, a school district may have the effect of dividing the district into separate, identifiable and unrelated units. Such a determination is essentially a question of fact to be resolved by the trial court in the first instance, but such cases must be rare. In the absence of such a determination, proof of state-imposed segregation in a substantial portion of the district will suffice to support a finding by the trial court of the existence of a dual system. Of course, where that finding is made, as in cases involving statutory dual systems, the school authorities have an affirmative duty "to effectuate a transition to a racially nondiscriminatory school system." Brown II, supra, at 301.