Who ruled the "separate but equal" doctrine invalid in 1954?

The U.S. Supreme Court ruled the "separate but equal" doctrine invalid in 1954 through the landmark decision in Brown v. Board of Education. This case was a pivotal moment in American civil rights history, as it effectively overturned the previous ruling in Plessy v. Ferguson, which had established the legality of racial segregation under the premise that separated facilities could be deemed equal.

The Supreme Court recognized that segregation in public schools created a sense of inferiority among African American children that could not be remedied by any purportedly equal facilities. The unanimous ruling declared that segregation in public education was inherently unequal, thus violating the Equal Protection Clause of the Fourteenth Amendment. This decision was instrumental in the civil rights movement, as it served as a legal foundation for challenging segregation and discrimination across various areas of society, leading to significant changes in laws and attitudes regarding racial equality.

The involvement of the U.S. Congress, President, or State Supreme Courts was not the basis for this ruling; the authority of the Supreme Court was central in interpreting the Constitution and establishing this precedent.