Final answer:
The Supreme Court case Brown v. Board of Education challenged the 'separate but equal' doctrine and declared racially segregated schools unconstitutional, overturning the Plessy v. Ferguson decision and making a significant advancement in the civil rights movement.
Step-by-step explanation:
The landmark Supreme Court case, Brown v. Board of Education of Topeka, fundamentally challenged the "separate but equal" doctrine that was established by Plessy v. Ferguson in 1896. This doctrine had provided the legal justification for racial segregation in public facilities, including schools. The Brown case concluded that separate educational facilities were inherently unequal, thereby violating the Equal Protection Clause of the Fourteenth Amendment. The Delaware case mentioned refers to one of the cases consolidated under Brown v. Board of Education, where the Delaware plaintiffs had initially received some relief at the state level before the cases reached the Supreme Court. The unanimous decision of the Court in 1954 overruled the separate but equal precedent, marking a significant step in the civil rights movement by declaring segregated schools unconstitutional.
Not only did the decision establish that the physical facilities could never really be 'equal', but it also acknowledged the psychological impact of segregation on African American children's self-esteem and their sense of inferiority. The Delaware case was unique among the grouped cases in that the Delaware Supreme Court had previously ruled in favor of the plaintiffs, thereby marking a divergence from the separate but equal doctrine even before the consolidated Supreme Court decision.