It is undeniable that the great social movements of the last half of the 20th century changed the terrain on which millions live and how they understand the world in profound and enduring ways. And yet their transformative capacity, that is their ability to move to a new, higher stage of struggle and possibility, was circumscribed by the limited participation of the main sections of the labor movement. Few articulated this better than MLK in the 1960s. What was true in the last century is no less true in this century.