Change has come, gone away and come again in the realm of U.S. politics. But this moment in Democratic politics seems particularly potent: in state after state, the narrow, ironclad profile of who can run and who can win at the highest levels of politics has been irreversibly expanded.

The Citgo sign that resides directly above 660 Beacon St. is a beacon of hope for the city of Boston and its residents. It is a beacon for the marathon runners who can see it as they crest their final...