What did the Supreme Court support through their decisions in the case Plessy v. Ferguson 1886?

Segregation, by supporting the idea of "separate but equal"

Explanation:

Plessy v. Ferguson, 163 U. S. 537 (1896), was a landmark decision of the U. S. Supreme Court that upheld the constitutionality of racial segregation laws for public facilities as long as the segregated facilities were equal in quality - a doctrine that came to be known as "separate but equal".