The presidency of Donald Trump, nearly a year old, has revived a political debate that began in earnest in sixteenth-century Europe: does a nation require leaders of good moral character in order to flourish?

Niccolo Machiavelli, who witnessed the violent collapse of the Florentine Republic, famously answered the question in the negative: Politicians must often commit acts of evil to maintain public order and unity—and they shouldn’t be troubled by this reality. “How praiseworthy it is for a prince to keep his word and to live with integrity and not by cunning, everyone knows,” he wrote in The Prince (1513). “Nevertheless, one sees from experience in our times that the princes who have accomplished great deeds are those who have thought little about keeping faith and who have known how cunningly to manipulate men’s minds.”