The Plessy v. Ferguson case, decided in 1896, was crucial for the legislative branch as it established the "separate but equal" doctrine, legitimizing racial segregation laws. This ruling provided a legal foundation for the enactment of Jim Crow laws across the Southern states, influencing legislative actions and policies for decades. It underscored the power of the judiciary to interpret the Constitution and shaped the legislative landscape regarding civil rights and racial equality. Ultimately, the case prompted future legislative efforts aimed at dismantling segregation and promoting civil rights.