Final answer:
The Supreme Court's decision in Plessy v. Ferguson intended to constitutionally justify 'separate but equal' facilities, allowing de jure segregation in public accommodations as long as the separate facilities for different races were deemed equal.
Step-by-step explanation:
The intended effect of the reasoning in the Supreme Court case Plessy v. Ferguson was to provide a constitutional basis for separate but equal facilities for different races, effectively legitimizing segregation.
The Court argued that the Fourteenth Amendment mandated equality before the law, but not necessarily the abolition of racial distinctions in social settings.
The decision allowed states to enforce segregation as long as the separate facilities provided to each race were considered equal, although in practice, these facilities were rarely, if ever, truly equal.