Mr. Trump’s strength is strange. It is reminiscent not so much of the classic American strongman as it is of the conjectural German Superman. Could it be that Donald Trump is an incarnation of Nietzschean social philosophy? A man who has surpassed the common man? A fantasy icon of power, fame, riches, confidence, mass influence, and moral indifference? Is “The Donald†the Übermensch? Mr. Trump’s force-of-will, come-what-may, shoot-from-the-hip, couldn’t-care-less attitude is in keeping with the self-willed assertion of Nietzsche when it comes to the rejection of accepted moral and political norms. Breaking with custom was central to Nietzsche’s philosophy of...