Final answer:
The Supreme Court's decision in Plessy v. Ferguson was problematic since it endorsed 'separate but equal' facilities, upholding de jure segregation and hindering civil rights progress.
Step-by-step explanation:
The Supreme Court's ruling in Plessy v. Ferguson was problematic because it was based on the belief that segregation was permissible as long as the facilities were "separate but equal". The court upheld the constitutionality of a Louisiana law that mandated racial segregation on trains by confirming that segregation does not imply discrimination if the segregated facilities for both races were equivalent. The decision of the Supreme Court in Plessy v. Ferguson effectively reinforced racial discrimination under the guise of equal treatment and was a significant setback for Black Americans' civil rights. The concept of "separate but equal" established a legal groundwork for de jure segregation that lasted until it was overturned by the Supreme Court's decision in Brown v. Board of Education in 1954.