Final answer:
The Supreme Court in Plessy v. Ferguson maintained that laws mandating racial segregation were constitutional under the 'separate but equal' doctrine, with facilities for both races being equal and segregation not inherently implying discrimination or inferiority.
Step-by-step explanation:
In the case of Plessy v. Ferguson (1896), the majority of the Supreme Court maintained that Jim Crow laws mandating racial segregation were constitutional under the "separate but equal" doctrine. The facts involved Homer Plessy, a man of mixed racial heritage, who was arrested for sitting in a whites-only railroad car. Plessy argued that the equal protection clause of the Fourteenth Amendment was violated by Louisiana's segregation law. However, the Supreme Court ruled that as long as the separate facilities for blacks and whites were equal, segregation did not imply discrimination or inferiority and thus did not violate the constitution.
De jure segregation, or legal segregation, was therefore deemed constitutional by the court's ruling. The court's opinion reinforced the doctrine of "separate but equal," founding its justification on tradition, social customs, and the supposed maintenance of public peace and order. The Plessy v. Ferguson decision upheld state laws requiring the separation of races in public places, legitimizing a brand of discrimination that would persist until the civil rights movement significantly challenged and eventually overturned such statutes.