What legal and ethical arguments did white Americans use to justify segregations?

The argument that Thurgood Marshall used to challenge the legality of segregation in Brown v. Board of Education was that “separate but equal” facilities were unequal and that it did great damage to black children as segregation was a form of discrimination that instilled a sense of inferiority to African Americans children and undermined their self-esteem. Consequently, it was a law that violated the 14th Amendment, an amendment that guaranteed all citizens equal protection of the laws.