<P> The NAACP had accepted and litigated other cases, including that of Irene Morgan in 1946, which resulted in a victory in the U.S. Supreme Court on the grounds that segregated interstate bus lines violated the Commerce Clause . That victory, however, overturned state segregation laws only insofar as they applied to travel in interstate commerce, such as interstate bus travel, and Southern bus companies immediately circumvented the Morgan ruling by instituting their own Jim Crow regulations . Further incidents continued to take place in Montgomery, including the arrest for disorderly conduct in May 1951 of Lillie Mae Bradford, who refused to leave the white passengers' section until the bus driver corrected an incorrect charge on her transfer ticket . </P> <P> On February 25, 1953, the Baton Rouge, Louisiana city - parish council passed Ordinance 222, after the city saw protesting from African - Americans when the council raised the city's bus fares . The ordinance abolished race - based reserved seating requirements and allowed the admission of African - Americans in the front sections of city buses if there were no white passengers present, but still required African - Americans to enter from the rear, rather than the front of the buses . However, the ordinance was largely unenforced by the city bus drivers . The drivers later went on strike after city authorities refused to arrest Rev. T.J. Jemison for sitting in a front row . Four days after the strike began, Louisiana Attorney General and former Baton Rouge mayor Fred S. LeBlanc declared the ordinance unconstitutional under Louisiana state law . This led Rev. Jemison to organize what historians believe to be the first bus boycott of the civil rights movement . The boycott ended after eight days when an agreement was reached to only retain the first two front and back rows as racially reserved seating areas . </P> <P> Black activists had begun to build a case to challenge state bus segregation laws around the arrest of a 15 - year - old girl, Claudette Colvin, a student at Booker T. Washington High School in Montgomery . On March 2, 1955, Colvin was handcuffed, arrested and forcibly removed from a public bus when she refused to give up her seat to a white man . At the time, Colvin was an active member in the NAACP Youth Council; Rosa Parks was an advisor . Colvin's legal case formed the core of Browder v. Gayle, which ended the Montgomery bus boycott when the Supreme Court ruled on it in December 1956 . </P> <P> In November 1955, just three weeks before Parks' defiance of Jim Crow laws in Montgomery, the Interstate Commerce Commission, in response to a complaint filed by Women's Army Corps private Sarah Keys, closed the legal loophole left by the Morgan ruling in a landmark case known as Keys v. Carolina Coach Co...The ICC prohibited individual carriers from imposing their own segregation rules on interstate travelers, declaring that to do so was a violation of the anti-discrimination provision of the Interstate Commerce Act . But neither the Supreme Court's Morgan ruling nor the ICC's Keys ruling addressed the matter of Jim Crow travel within the individual states . </P>

When did the supreme court rule that bus segregation was unconstitutional