OPINION OF THE COURT
ALDISERT, Circuit Judge.The major question presented in this review of a three-judge court’s judgment ordering the Delaware Board of Education to desegregate its school system is the propriety of the court’s inter-district remedy. As hereinafter modified, the district court’s judgment will be affirmed.
The present appeal is, we trust, the final chapter in an extensive series of proceedings initiated twenty years ago “to eliminate the de jure segregation in Delaware schools,” Evans v. Buchanan, 393 F.Supp. 428, 430 (D.Del.1975), and to effectuate “a transition to a racially nondiscriminatory school system” as required by Brown v. Board of Education (Brown II), 349 U.S. 294, 301, 75 S.Ct. 753, 756, 99 L.Ed. 1083 (1955).1 A three-judge court was convened in 1971 in response to the plaintiffs’ concern that Delaware’s Educational Advancement Act of 1968, which gave the State Board of Education the power to reorganize existing school districts, 14 Del.C. § 1001, but excluded the Wilmington school district from reorganization, see id. §§ 1004(c)(2) and (4), 1005, 1021, 1026(a), offended the principles of Brown.
In its initial opinion, Evans v. Buchanan, 379 F.Supp. 1218 (D.Del.1974), the court concluded that “segregated schooling in Wilmington has never been eliminated and that there still exists a dual school system,” id. at 1223, and, accordingly, ordered the State Board of Education to submit plans to remedy existing segregation. Id. at 1224. The court postponed the date set for submission of the plans, however, after the Supreme Court issued its opinion in Milliken v. Bradley, 418 U.S. 717, 94 S.Ct. 3112,41 L.Ed.2d 1069 (1974). In its 1975 deliberations, having invited all affected school districts to present evidence on all issues before the court, and applying Milliken standards to the record evidence thus adduced, the court found significant inter-district, de jure segregation in New Castle County. Evans v. Buchanan, 393 F.Supp. 428, 431-32, 438, 445, 447 (D.Del.1975). At this time, the court held unconstitutional those provisions of Delaware’s Educational Advancement Act which excluded Wilmington from eligibility for reorganization, and again ordered submission of both Wilmington-only and inter-district plans to remedy the inter-district segregation. Id. at 447. The State Board of Education and the intervening suburban school districts (except DeLa-Warr) appealed this judgment to the Supreme Court pursuant to 28 U.S.C. § 1253. On November 17, 1975, the Supreme Court summarily affirmed the district court. Buchanan v. Evans, 423 U.S. 963, 96 S.Ct. 381, 46 L.Ed.2d 293 (1975).
On May 19, 1976, after three weeks of evidentiary hearings on the plans submitted by the parties, the district court reiterated its finding of an inter-district violation: “We establish here only that the remedy which we order may include the suburban districts, because their existence and their actions were part of the violations which lead to the remedy.” Evans v. Buchanan, 416 F.Supp. 328, 341 n. 43 (D.Del.1976). In considering the various plans submitted, the court found Wilmington-only plans unacceptable, id. at 343-44, and rejected the *377specific inter-district remedies proposed by the parties. The latter included plans relying on voluntary transfer inducement (“magnet” plans), id. at 345-46, and several -proposals utilizing cluster and pairing techniques, id. at 346-48, which the court determined to be “fraught with complex problems unsuitable for judicial determination” and which would “place the Court in the ongoing position of general supervisor of education in New Castle County.” Id. at 347.
On June 15, 1976, the district court ordered that Delaware schools in the area north of the northern line of the Appoquin-imink School District — the area presently comprised of the Alfred I. duPont, Alexis I. duPont, Claymont, Conrad, DeLaWarr, Marshallton-McKean, Mount Pleasant, Newark, New Castle-Gunning Bedford, Stanton, and Wilmington School Districts— be desegregated and reorganized into a new or such other new districts as would comply with the court’s May 19, 1976 opinion. The May 19 opinion had set the date for full compliance with constitutional requirements on all grade levels as September 1978. 416 F.Supp. at 361.
Thereafter, appellants took an appeal to the Supreme Court which, on November 29, 1976, dismissed the appeal on jurisdictional grounds. 423 U.S. 1080, 96 S.Ct. 868, 47 L.Ed.2d 91 (1976). The present protective appeals to this court were then pursued.
I.
The Supreme Court’s summary affirmance of the district court’s 1975 order would appear to be binding on this court under the law of the case principle, which has been explained by the Supreme Court as follows:
When matters are decided by an appellate court, its rulings, unless reversed by it or a superior court, bind the lower court. Thus a cause proceeds to final determination. While power rests in a federal court that passes an order or decision to change its position on a subsequent review in the same cause, orderly judicial action, except in unusual circumstances, requires it to refuse to permit the relitigation of matters or issues previously determined on a former review.
Insurance Group Committee v. Denver & Rio Grande Western R. R., 329 U.S. 607, 612, 67 S.Ct. 583, 585, 91 L.Ed. 547 (1947) (footnote omitted).
Under the rule of Hicks v. Miranda, 422 U.S. 332, 344-45, 95 S.Ct. 2281, 45 L.Ed.2d 223 (1975), lower courts, being bound by summary decisions of the United States Supreme Court, may not reexamine constitutional questions necessarily decided in a summary affirmance. In cases of summary adjudication, of course, it is not always crystal clear what exactly was adjudicated by the Supreme Court, see Super Tire Engineering Co. v. McCorkle, 550 F.2d 903, 906 (3d Cir. 1977), but in this case we conclude that the Supreme Court affirmed the finding of one or more inter-district constitutional violations. The district court found a constitutional violation and ordered the parties to submit both Wilmington-only and inter-district plans. Thus, in exercising its review function, the Supreme Court perforce considered both the constitutional violation and its inter-district character. Had the Court disapproved of these lower court findings, it would either have found no constitutional violation, thereby precluding the submission of any plan, or, alternatively, it would have prohibited the filing of an inter-district plan.
The dissent urges that we should determine which of the eight violations found by the district court were affirmed or not affirmed by the Supreme Court. In view of the doctrine of the law of the case and the very brief order by the Supreme Court, this would become a highly speculative exercise, if indeed, this court has the power to attempt a modification of the Supreme Court’s judgment. If the defendants believe that some of the eight alleged violations were not affirmed, they should take, or perhaps previously should have taken, appropriate steps to obtain review of this matter, or a clarification, by the Supreme Court. To order a remand and further proceedings by the district court might well *378impose an unsolvable problem upon the district court.2
The law of the case principle also precludes this court from entertaining appellants’ suggestion that the Supreme Court’s decision of November 17, 1975, was somehow altered by its June 7, 1976, decision in Washington v. Davis, 426 U.S. 229, 96 S.Ct. 2040, 48 L.Ed.2d 597 (1976). The short answer is that it remains for the Supreme Court, not an “inferior” tribunal, to entertain this contention. Insurance Group Committee v. Denver & Rio Grande Western R. R., supra. Nor are we persuaded that the Davis decision constitutes an “unusual circumstances” exception to the law of the case, in view of the Supreme Court’s own explanation that “the holding in Davis reaffirmed a principle well established in a variety of contexts. E. g., Keyes v. School District No. 1, 413 U.S. 189, 208, 93 S.Ct. 2686, 2697, 37 L.Ed.2d 548 (1973) (schools); Wright v. Rockefeller, 376 U.S. 52, 56-57, 84 S.Ct. 603, 605, 11 L.Ed.2d 512 (1964) (election districting); Akins v. Texas, 325 U.S. 398, 403-404, 65 S.Ct. 1276, 1279, 89 L.Ed. 1692 (1945) (jury selection).” Village of Arlington Heights v. Metropolitan Housing Development Corp., 429 U.S. 252, 97 S.Ct. 555, 50 L.Ed.2d 450 (1977). We hold, therefore, that one or more inter-district constitutional violations were found by the district court and affirmed by the Supreme Court. Those rulings now constitute the law of the ease. Accordingly, we are precluded from re-examining them. Instead, our concentration must be upon the court-ordered remedy.
II.
A.
Before considering the specifics of the remedy ordered by the district court, it is important to emphasize that, as a reviewing court, we are not empowered to consider the matter de novo. The fashioning of a remedy is committed to “the exercise of the district judge’s discretion . [and] a school desegregation case does not differ fundamentally from other cases involving the framing of equitable remedies to repair the denial of a constitutional right.” Swann v. Board of Education, 402 U.S. 1, 15-16, 91 S.Ct. 1267, 1276, 28 L.Ed.2d 554 (1971).3
The Supreme Court teaches that this exercise of discretion involves certain functional parameters:
[Discretion imports not the court’s “inclination, but ... its judgment; and its judgment is to be guided by sound legal principles.” Discretion is vested not for purposes of “limitpng] appellate review of trial courts, or inviting] inconsistency and caprice,” but rather to allow the most complete achievement of the objectives . attainable under the facts and circumstances of the specific case.
Franks v. Bowman Transportation Co., 424 U.S. 747, 770-71, 96 S.Ct. 1251, 1267, 47 L.Ed.2d 444 (1976), quoting Albermarle Paper Co. v. Moody, 422 U.S. 405, 421, 95 S.Ct. 2362, 45 L.Ed.2d 280 (1975). And in a recent delineation of the proper appellate role for reviewing exercise of discretion, this court stated that an improper use of discretion exists only when the judicial action is arbitrary, fanciful, or unreasonable, or when improper standards, criteria, or procedures are used. Lindy Bros. Builders, *379Inc. v. American Radiator and Standard Sanitary Corp., 540 F.2d 102,115-16 (3d Cir. 1976) (in banc).
Thus, our task on review is not to substitute the remedy we would have imposed had we been the district court; rather, it is to determine whether the district court observed promulgated guidelines.
B.
The sound legal principles that govern the remedy in this case have been enunciated by the Supreme Court.4 The Supreme Court’s school desegregation opinions have consistently emphasized the basic and universal remedial purposes of a desegregation order as well as the intensely practical and unique character of each such order. At the same time the Court has set certain outer limitations upon the exercise of remedial discretion in school desegregation cases.
The guiding purpose of a remedial order in a case such as this is to eliminate unconstitutional racial discrimination “root and branch”. Green v. County School Board, 391 U.S. 430, 438, 88 S.Ct. 1689, 20 L.Ed.2d 716 (1968). The school system and its students are to be returned, as nearly as possible, to the position they would have been in but for the constitutional violations that have been found.
While the purposes of such a remedy are broad, the details of its structure must necessarily be specific. The plan adopted should be one that promises “realistically to work” in overcoming the effects of discrimination. Green v. County School Board, supra, 391 U.S. at 439, 88 S.Ct. 1689. “Having once found a violation, the district judge or school authorities should make every effort to achieve the greatest possible degree of actual desegregation, taking into account the practicalities of the situation. . The measure of any desegregation plan is its effectiveness.” Davis v. Board of School Commissioners, 402 U.S. 33, 37, 91 S.Ct. 1289, 1292, 28 L.Ed.2d 577 (1971). The realities and practicalities of each particular case are necessarily matters within the trial court’s discretion.
While the unique character of every school system has prevented the Supreme Court from promulgating detailed rules concerning what a court must do to remedy a constitutional violation, the Supreme Court has specified what a court may not do in such a case. A court is not at liberty to issue orders merely because it believes they will produce a result which the court finds desirable. The existence of a constitutional violation does not authorize a court to seek to bring about conditions that never would have existed even if there had been no constitutional violation. The remedy for a constitutional violation may not be designed to eliminate arguably undesirable states of affairs caused by purely private conduct (de facto segregation) or by state conduct which has in it no element of racial discrimination. This much is settled by Milliken v. Bradley, supra. See also Spencer v. Kugler, 404 U.S. 1027, 92 S.Ct. 707, 30 L.Ed.2d 723 (1972), affirming 326 F.Supp. 1235 (D.N.J.); Village of Arlington Heights v. Metropolitan Housing Development Corp., 429 U.S. 252, 97 S.Ct. 555, 50 L.Ed.2d 450. Nor may a remedial desegregation order require “as a matter of substantive constitutional right, any particular degree of racial balance or mixing . The constitutional command to desegregate schools does not mean that every school in every community must always reflect the racial composition of the school system as a whole.” Swann v. Board of Education, supra, 402 U.S. at 24,91 S.Ct. at 1280. If that language were not clear enough, the Supreme Court has more recently repeated that “[t]he clear import of this language from Swann is that desegregation, in the sense of dismantling a dual school system, does not require any particular racial balance in each ‘school, grade or classroom.’ ” Milliken v. Bradley, 418 U.S. at 740-41, 94 S.Ct. at 3125 (footnote omitted). These are *380limitations by which a trial court must abide.
The task of a remedial decree in a school desegregation case is simply to correct the constitutional violation and to eradicate its effects. “As with any equity case, the nature of the violation determines the scope of the remedy.” Swann v. Board of Education, supra, 402 U.S. at 16, 91 S.Ct. at 1276.
III.
Formulating a realistic, practical, and effective remedy is a job peculiarly within the province of the trial court, whose position gives it a quantum advantage over an appellate court in weighing the “practicalities of the situation”. It is primarily for this reason that we defer to the trial court’s exercise of remedial discretion when it has applied proper legal precepts and remained within determined legal boundaries. See Lindy Bros., supra, 540 F.2d at 116. Perhaps not all of the judges on this court would have promulgated the remedy prescribed by the district court. But given the nature of the judicial system — in Roscoe Pound’s formulation, “a body of traditional ideas as to how legal precepts should be interpreted and applied and causes decided, and a traditional technique of developing and applying legal precepts”5 — this court is required to follow a narrow compass.6 Viewed in this context, we cannot say that the result ordered by the district court was a misuse of discretion.
Although we find no misuse of discretion in the basic concept of the remedy, we are disturbed by language in the district court’s opinion which can be interpreted as requiring an enrollment of 10-35% black students in each grade. 416 F.Supp. at 356-57. The district court explained this language as follows: “We do not propose the imposition of definitive racial quotas for particular schools. . . . What we set forth here is not a determination of a ‘quota’. Rather, it is a statement of what will be considered a desegregated school upon any necessary review of actual assignments made by local officials.” Id. at 356. Although we accept the district court’s explanation that no definitive racial quota was intended, we also believe that this aspect of its opinion might be misunderstood. The Supreme Court has clearly stated that “desegregation, in the sense of dismantling a dual school system, does not require any particular racial balance in each ‘school, grade, or classroom.’ ” Milliken v. Bradley, supra, 418 U.S. at 741, 94 S.Ct. at 3125. We are not free to ignore that statement. Accordingly, and to avoid any possible misunderstanding, we expressly disapprove the 10-35% enrollment criterion, and we specifically hold that no particular racial balance will be required in any school, grade, or classroom.
For the reasons set forth in Part II, supra, we affirm the basic concept of the remedy ordered by the district court. Those portions of the district court opinion capable of a meaning at variance with the principles stated in Part II, supra, are not embraced by this court; those portions of the district court’s opinion capable of being construed as inconsistent with Part II, supra, will be modified so as to remove the possibility of inconsistency or ambiguity.
IV.
In ordering reorganization or consolidation of the New Castle County school districts, the district court stressed that “the State Legislature and the State Board of Education may take such steps as are not violative of constitutional rights to change the pattern set here,” 416 F.Supp. at 357, and ordered creation of an interim board to operate the schools “for so long as the State takes no action.” Id. We specifically af*381firm this governance plan and emphasize that prompt compliance by the state may make action by the interim board unnecessary. Moreover, we do not mandate any specific number of districts which the state may create within the area presently encompassed by the defendant districts nor do we require that all the existing districts be reconstituted. We do caution that a “Wilmington only” plan will not be adequate. We add one additional provision. We shall require State authorities to file with the district court within 60 days from the date hereof a formal report of its efforts to carry out the mandate of the district court.
V.
To eliminate the necessity for additional proceedings in the district court, we now set forth the specific order to be entered upon the return of the mandate of this court:
JUDGMENT
For the reasons set forth in the opinion of the Court of Appeals for the Third Circuit, filed May 18, 1977 and Parts VI, VI A, VI C, VII, VII A, VII B, VII C, VII D, VIII, IX, IX B, and IX C of the Opinion of this Court issued May 19,1976, IT IS HEREBY ORDERED AND DECREED:
1. (a) That this action shall be maintained as a class action, and the class shall consist of all black and Hispanic children presently enrolled in the Wilmington, Delaware School system, and that the representation of the Intervening Plaintiffs Pacheco, Rodriguez, et al., is limited to the protection of the interests of the Hispanic students who are members of the class, in receiving bilingual education;
(b) That the class so defined shall be represented by the named plaintiffs before the Court who are members of the class, through their parents, legal guardians, or next friends;
2. That the schools in that area of Delaware north of the northern line of the Appoquinimink School District; that is, the area presently comprised of the Alfred I. duPont, Alexis I. duPont, Clay-mont, Conrad, DeLaWarr, Marshallton-McKean, Mount Pleasant, Newark, New Castle-Gunning Bedford, Stanton, and Wilmington School Districts, shall be desegregated in accordance with the Opinion of the Court of Appeals for the Third Circuit, and shall be reorganized into a new or such other new districts as shall be prescribed by the state legislature or the State Board of Education, so long as such prescription shall comply with that opinion, thereby eliminating the dual school system (379 F.Supp. 1218, 1223) and the vestige effects of de jure segregation;
3. The State Board of Education or other appropriate State authority shall file a formal report in accordance with Part IV of the Opinion of the Court of Appeals of the Third Circuit within 60 days from May 18, 1977 (date of filing this opinion);
4. The State Board of Education shall, if the state legislature or the State Board of Education do not promptly comply with paragraph 2 of this Order:
(a) Appoint a board of five members (the “New Board”) to oversee the operation of the schools of the area as defined in ¶ 2 of this Order, such members to be appointed so that one member of the New Board shall be a member of the present Newark School Board; one member of the New Board shall be a member of the present Wilmington School Board; one member of the New Board shall be a member of either the present New Castle-Gunning Bedford, or DeLaWarr or Conrad School Boards; one member of the New Board shall be a member of the present Stanton, Marshallton-McKean, or Alexis I. duPont School Boards; and one member of the New Board shall be a member of either the present Alfred I. duPont, Mount Pleasant or Claymont School Boards; and that the members of the New Board so appointed shall serve until their successors are selected and duly qualified:
*382(b) Cooperate and assist the New Board in all planning and operational phases of the implementation of a plan which shall be designed to desegregate the schools in accordance with the Opinion of the Court of Appeals;
(c) Exercise appropriate supervision of the New Board or its successor or successors and its exercise of authority;
(d) Set a date certain for the transfer of full responsibility for the operation of the schools to the New Board or such successor or successors designated by state law; such.date to be prior to September 1, 1977;
(e) Be responsible, together with the presently existing boards, for any expenses created by the operation of the New Board or its successor or successors until such time as the New Board or its successor or successors, in a transfer of authority, receive taxing power, in accordance with ¶ 4(d) hereof, and state law;
5. The New Board or its successor or successors shall:
(a) Commence immediately upon appointment to consider any necessary planning for the transfer to it of operating authority;
(b) Prepare a plan for the operation of unitary desegregated schools, in accordance with the Opinion of the Court of Appeals;
(c) Accept responsibility for the operation of the schools, beginning with the Fall, 1977 term, in accordance with a timetable to be set by the State Board of Education;
6. The existing boards of the present school districts shall assist in the transfer of authority, and shall be liable together with the State Board for the expenses of the New Board or its successor or successors, until such time as the New Board or its successors receive taxing authority, in accordance with ¶ 4(d) hereof, and state law; the aforesaid expenses of the New Board shall be borne by the existing boards of the present school districts and by the State Board; each existing board’s contribution being assessed in proportion to the ratio which the assessed value of taxable property in that present school district bears to the total assessed value of taxable property in all districts; provided, however, that each existing board’s contribution shall be reduced from the aforesaid .sum by virtue of the State Board’s required contribution, which contribution shall equal the largest contribution required from any of the local boards;
7. The State Board, in cooperation with the existing local districts, may assign members of the professional staff of the Department of Public Instruction or the local districts, to assist the New Board during the period prior to September, 1977;
8. Upon the transfer of full authority to the New Board or its successors, the present boards shall, in accordance with state law, cease to exist;
9. The provisions of Paragraphs 1 through 8 of this Order in accordance with VII D of the Opinion of this Court of May 19, 1976, shall be inapplicable to the New Castle County Vocational-Technical School District;
10. The application of the plaintiff class for an injunction to restrain the payment by the State of any subsidy for the transportation of students to private schools is denied;
11. The provisions of Paragraphs 2 and 8 of this Order shall be stayed in accordance with VI C of the Opinion of this Court of May 19, 1976; and
12. The three-judge panel convened for the purpose of considering the above matters is dissolved, and supervisory jurisdiction will remain in the District Court, in accordance with provision IX C of the Opinion of May 19,1976 and the mandate of the Court of Appeals for the Third Circuit in Evans v. Ennis, 281 F.2d 385, 391 n. 1 (1960).
As so modified, the judgment of the district court will be affirmed. The mandate of the court will issue forthwith.
. For a comprehensive history of this litigation, see Evans v. Buchanan, 379 F.Supp. 1218, 1220-21 (D.Del.1974).
. The three-judge district court that considered the eight alleged violations has now been dissolved. In its stead a single district judge, the Honorable Murray Schwartz, has been appointed. Thus, under the view expressed by the dissent, Judge Schwartz would undoubtedly have to hear de novo all the evidence regarding the alleged violations and then determine, anew, whether there is sufficient evidence to support the findings regarding these alleged violations.
. That the remedy was promulgated by a three-judge court instead of a single judge need not detain us. Even where the convening of a three-judge court was unnecessary, see, e. g., Board of Regents v. New Left Education Project, 404 U.S. 541, 92 S.Ct. 652, 30 L.Ed.2d 697 (1972), the critical jurisprudential effect is that appeal lies to this court. See Phillips v. United States, 312 U.S. 246, 61 S.Ct. 480, 85 L.Ed. 800 (1941); Moody v. Flowers, 387 U.S. 97, 104, 87 S.Ct. 1544, 18 L.Ed.2d 643 (1967).
. We note that Congress has declared, inter alia, as “the policy of the United States,” that “all children enrolled in public schools are enti-tied to equal educational opportunity without regard to race, color, sex or national origin ...” 20 U.S.C. § 1701(a).
. Pound, The Theory of Judicial Decision, 36 Harv.L.Rev. 641, 645 (1923).
. We note also that a reviewing court may approve the judgment of a reviewed court without embracing its ratio decidendi: “[W]e may affirm a judgment of the district court if the result is correct even though our reasoning be inconsistent with that of the trial court.” Rhoads v. Ford Motor Co., 514 F.2d 931, 934 (3d Cir. 1975).