Successful end to legal segregation

 After World War II, African Americans in the South successfully ended legal segregation and restored their voting rights which had been largely lost since the end of Reconstruction.  What persons, organizations, events, and legislation led to these victories?  What in American society had changed, for example, economically, politically, and technologically that enabled the Civil Rights Movement to succeed? Why did the movement sputter out as the 1960s drew to a close?