who argued before the supreme court that separate schools violate the fourteenth amendment
Thurgood Marshall
Brown v. Board of Education
 The Browns, then represented by NAACP chief counsel Thurgood Marshall, appealed to the Supreme Court, which agreed to hear the case. 
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Brown v. Board of Education [SEP] Introduction
Ferguson", in which the Court had ruled that racial segregation was not in itself a violation of the Fourteenth Amendment's Equal Protection Clause if the facilities in question were otherwise equal, a doctrine that had come to be known as "separate but equal". The Browns, then represented by NAACP chief counsel Thurgood Marshall, appealed to the Supreme Court, which agreed to hear the case. The Court's decision in "Brown" partially overruled "Plessy v. Ferguson" by declaring that the "separate but equal" notion was unconstitutional for American public schools and educational facilities. It paved the way for integration and was a major victory of the Civil Rights Movement, and a model for many future impact litigation cases.