The upbeat lyric by Ira Gershwin quoted in the epigraph, set to a bouncy, captivating melody recovered from the papers left by his recently deceased brother George, served as the official anthem of the 1939–40 New York World’s Fair. “Dawn of a New Day,” like the fair itself, exemplified one sort of possible response to recent, worrisome historical events. Its metaphors were not very fresh—gray skies, the wolf at the door—but the message was none the less attractive for that. Perhaps the hard …