What best symbolizes black progress--and white resistance--in America is the march. Haggard slaves marched north, using moonlight and north-facing moss to get to freedom. Years later, regiments of blacks again marched north, this time in the great migration, drawn by jobs and away from Jim Crow. In the civil rights struggles of the 1960s, the most poignant images were of the march: from Selma to Montgomery, then to Washington and the Lincoln Memorial to hear Martin Luther King Jr. tell of a dream. New laws signaled the next campaign: blacks and whites heading toward an integrated, egalitarian society.
But decades later,...