As Americans have become more polarized, has Hollywood shied away from telling overtly political stories? Turner Classic Movies host Ben Mankiewicz talks with actor Martin Sheen, best known as the president of the long-running TV series “The West Wing”; with film professor Annette Insdorf and critic Michael Schulman, on Hollywood’s long tradition of political cinema; and former studio head Michael Lynton, on the thinking behind risk-averse film studios.