What wa the importance of the plessy v. ferguson (1896) decision by the supreme court

It was a milestone in the history of racial segregation. In 1896 the US Supreme Court took a decision that support the constitutionality of racial segregation in the time of  ¨separate but equal¨ doctrine. The case originated when an African-American train traveller refused to sit in a car for blacks. The Supreme court refused Plessy's argument stating  that a law that indicates a legal distinction between whites and blacks was not unconstitutional.    

during the hitler era and it caused them to declare war on germany