Donald Trump is the undisputed hero of this comic opera in three acts. “Comic” does not here mean superficial or laugh-out-loud hilarious: as Rossini so superbly demonstrated in “The Barber of Seville”, comic opera combines a sophisticated analysis of human interactions with a light touch. Foreign policy offers plenty of opportunities to study human nature; at summits, each participant brings not only his or her personality but a country’s sensitivities, strengths and weaknesses to bear. Like Bartolo—the central character in “The Barber of Seville”, a buffoon-like doctor of medicine with ambitions that supersede his abilities—Mr Trump is sung by a bass.