The Plessy v. Ferguson Supreme Court decision of 1896 established the "separate but equal" doctrine regarding public facilities and services used by African Americans, thus ushering in an era of legally-based or de jure segregation. Plessy was followed by six cases in the field of education over the next five decades, all of which involved the 'separate but equal' doctrine: Cumming v. County Board of Education; Gong Lum v. Rice; Missouri ex rel Gaines v. Canada; Sipuel v. University of Oklahoma; Sweat v. Painter; and McLourin v. Oklahoma State Regents. While the first two cases did not challenge the validity of the "separate but equal" doctrine, the remaining ones, all concerning higher education institutions, found inequality in the benefits enjoyed by white students but denied black students with the same educational qualifications.

The "separate but equal" doctrine began to erode in 1950 with the Sweat v. Painter case, in which a black student was barred from the University of Texas Law School and consigned to a separate all-black facility. The Supreme Court noted in this case that the white school offered, among other things, a larger faculty, more course variety, and a better library. Because the inequality of the two institutions was established, the court ordered the plaintiff's admission to the white law school but refused to rule on the constitutionality of the Plessy "separate but equal" doctrine. Nevertheless, the "separate but equal" doctrine was ruled unconstitutional four years later in Brown v. Board of Education of Topeka.  While the Brown decision ruled that "separate but equal" was a violation of the Equal Protection Clause of the 14th Amendment, it did not stipulate immediate relief. The question of relief was set for re-argument, and an invitation to submit briefs to aid in the formulation of relief was extended to the U.S. Attorneys General and the states where de jure school segregation was imposed. The re-argument was held a year later in Brown II (1955), in which the Court mandated the elimination of racial discrimination in public schools and assigned roles to local school authorities and federal district courts in implementing the transition to unitary school systems.

However, the Court still failed to provide clear guidelines to end de jure segregation in public schools and therefore the federal district judges began their quest for desegregation with very little guidance from the Supreme Court. The Court's lack of clear guidance and imprecise time frame, especially in those areas of the South where there was considerable animosity towards the decision, contributed to attempts at delay if not outright noncompliance with Brown. Some school systems attempted to close public schools rather than desegregate, while others adopted "freedom of choice" plans that allowed students to choose the school where they would enroll, which resulted in continued segregation. Even where local authorities were attempting to implement a desegregation plan, these efforts were sometimes thwarted by state-level action. The result was that a decade after Brown little desegregation had occurred.

The turning point for the end of state-level segregation policies and the beginning of the desegregation era was the Green decision of 1968, but the foundation for the impact of Green lay in the Civil Rights Act of 1964 and the Elementary and Secondary Education Act of 1965. These Acts were crucial for a number of reasons, foremost of which was the provision of federal funds to eliminate segregation. Specifically, these Acts permitted the Department of Health, Education, and Welfare (HEW) to terminate funding in segregated districts and allowed the Justice Department to initiate integration proceedings. The Green decision was significant because for the first time the Court provided clear guidelines of what was expected in term of desegregation. Green involved a small school district in Virginia with two schools: one for the white children and one for the blacks. The threat of losing funds under enforcement through the Civil Rights Act led the county to adopt a freedom-of-choice plan calling for students to select one of the two schools. But no white children attended the black school, and only 15% of the black children were enrolled in the white school.

Although the Court did not deem freedom-of-choice plans unconstitutional, it did reject them as an insufficient means of effectuating desegregation. The Court affirmed that any plan proposed was permissible only if it offered real promise of contributing to desegregation. Additionally, the Court laid down important guidelines concerning desegregation plans which meant that local authorities would now be held accountable not only for their affirmative acts but for their acts of omission as well. Therefore from this point on, desegregation plans would be judged by their effectiveness in eliminating formerly white and black schools; in other words, the courts would have to apply a 'results' test based on the racial composition of the schools. The guidelines set forth in the Green decision became the criteria by which school districts seeking unitary status were evaluated. These guidelines subsequently became known as the Green factors and included criteria for racial balance and equity in the following areas: student assignments, faculty, staff, transportation, extracurricular activities, and facilities.

Three years after Green, the Court further refined the scope of duty to eliminate dual school systems in Swann v. Charlotte-Mecklenburg Board of Education by setting targets for racial balance. This decision also affirmed the use of busing as a permissible means to achieve racial balance. Interestingly, in claiming that racial balance formulas and cross-district busing were reasonable and feasible remedies, this case did not examine the possibility that opposition to such policies could undermine their effectiveness and create resegregation between a city and its suburbs or between public and private schools.  In addition, the Swann decision emphasized the limits of the district courts' remedial powers in enforcing specific desegregation remedies. Nevertheless, within months of the Swann decision, over 40 plans throughout the South were formulated using the targets for racial balance set by the case.

Up until the Swann decision, the federal courts had limited its rulings to de jure segregation in public schools. Therefore while many districts in the South implemented desegregation plans under court order, the same trend was not occurring in the non-Southern states where law did not impose segregation but it was nonetheless present. In the North, several states, including Massachusetts and Connecticut had enacted racial balance laws in an effort to desegregate the public school system. However, such state laws had little influence - at least initially - on integration. In addition, HEW created under President Eisenhower in 1955, had some success negotiating local desegregation plans in the non-Southern states without going to court. But the more widespread and continued desegregation efforts in the southern states clearly revealed the lack of similar efforts in many non-Southern states where public school segregation did exist.

Non-Southern school segregation was primarily based on segregated housing patterns that allegedly were not the result of direct state action. In the 1973 Keyes v. School District of Denver, the Court expanded Brown to include this type of segregation known as de facto.  Subsequently, the decision led to a series of non-Southern desegregation lawsuits in such cities as Los Angeles and Stockton, California; Wilmington, Delaware; Indianapolis, Indiana; Boston and Springfield, Massachusetts; Detroit, Michigan; Minneapolis, Minnesota; Omaha, Nebraska; and Dayton, Columbus, and Cleveland, Ohio. In addition, political factors were also importance in stimulating desegregation efforts in the North, including city and school board racial liberalism.

The next frontier was the boundary separating city from suburban school districts. As early as 1970, it had become apparent that segregated urban districts lost a portion of their white population to suburban areas and private schools when desegregation plans were implemented. This led many local authorities to seek inter-district desegregation remedies. This was the case in the City of Detroit that culminated in the Milliken v. Bradley decision of 1974. Because Detroit was a majority-black (64%) school district, and projected demographic trends indicated that it would become increasingly black in the near future, the district court concluded that an effective desegregation plan could not be attained within the confines of the city of Detroit system. This prompted the district court to order a massive metropolitan remedy whereby Detroit would be consolidated with 53 independent suburban districts and students would be bused between the city and suburbs to attain racial balance in all schools.

However, in Milliken, the Supreme Court ruled five to four that the suburban districts did not have to be included in the plan because neither the state of Michigan nor the suburban districts were guilty of collusion with city segregation. In other words, Milliken states that an inter-district remedy is not constitutional unless there is proof of an inter-district violation - i.e. a multi-district remedy can only be formulated for those districts whose own policies fostered discrimination, or if a state law caused the inter-district segregation. While the Court later found special circumstances to warrant a metropolitan, inter-district court order in a few sites such as Wilmington, Delaware and Louisville, Kentucky, Milliken essentially shut the door on central city-suburban district remedies to segregation. Since Milliken no further Supreme Court decisions have been made to expand school desegregation in the North.  Indeed, the Milliken decision has had a devastating effect on the ability of many local authorities to achieve desegregation. Because inner-city school systems, particularly in the North, were and continue to be majority black and surrounded by almost all-white suburbs, inter-district remedies are the only viable solution to school segregation - there are simply not enough white students in the city, or enough black students in the suburbs, to achieve desegregation without an inter-district remedy.  

Most observers consider the Milliken decision the beginning of the end of the Supreme Court's support of desegregation efforts. Less than five years after the Milliken decision, the Reagan Administration reduced the scope of the federal desegregation program. The Justice Department argued in some cases against the continuation of existing desegregation plans.  The trend away from proactive efforts to desegregation continued in the early 1990s with the decisions of Board of Education of Oklahoma City v. Dowell (1991), Freeman v. Pitts (1992), and lastly Missouri v. Jenkins (1995). These decisions hastened the reduction of federal oversight of desegregation efforts.