Many images that came out of Ferguson, Mo., last month looked like scenes from Birmingham, Ala., in the 1960s: the gun-wielding police officers, the sign-carrying protesters and the chants demanding equal treatment and human dignity. But that’s where the similarities ended. For all the righteous indignation it inspired, the Ferguson turmoil has become the latest in a series of flash-in-the-pan causes that peter out without inspiring lasting movements for racial justice. As an organizer for the Student Nonviolent Coordinating Committee (SNCC) in Mississippi during the ’60s, what I learned was the importance of organizing at the grass-roots and how even...