The man lives, quite literally, in a building serviced by a golden elevator. Somehow, he presented himself as the scourge of the elites. For decades, he built a persona based on the most conspicuous consumption and the crassest of excess--and then he won the presidency on an anti-establishment ticket. The unlikely rise of Donald J. Trump exemplifies the political paradox of the twenty-first century. In this new Gilded Age, the contrast between...