To anyone who grew up in the Albany area before cable television (or, as I did, in western Massachusetts, served only by Albany stations), the name Erastus Corning was inescapable. For 35 years he was the Democratic mayor of the city, and nightly broadcasts featured him prominently. Sharr White’s marvelous new play The True makes Corning (Michael McKean) a central character in a story of what political parties and machine politics once were and, by contrast, what they have become. It has scope, intelligence and terrific writing.