Liberals are right that a combination of rising economic inequality (even if the rise is gradual) with stalled economic mobility is an invitation to destructive social resentments. Americans will accept unequal economic outcomes in a fair system. They object when the results seem rigged. That way lies the Bastille.
So the question comes to liberals and conservatives: If social mobility is the goal, what are the solutions? What can be done to improve the quality of teachers in failing schools, to confront the high school dropout crisis, to encourage college attendance and completion, to reduce teen pregnancy, to encourage stable marriages, to promote financial literacy, to spark entrepreneurship?
Both Democrats and Republicans should have something to contribute to the development of this agenda. Neither party, however, currently has much to say. And this is not likely to change until the discussion turns from equality to mobility.