Mr. Trump appears to see the presidency as a giant megaphone for stoking racial and ethnic animus. It is not just that he pursues policies aimed at exacerbating divisions, like banning migrants from majority-Muslim nations or building a wall on the United States-Mexico border. He seeks to demonize those who oppose his policies as dangerous extremists out to destroy America. In cases where his critics are not white — whether congresswomen of color or a judge of Mexican heritage — Mr. Trump is eager to spotlight that fact.

The president is looking to divide Americans along color lines, to conjure a zero-sum vision of America in which whites must contend against nonwhites for jobs, wealth, safety and citizenship. He thinks this approach will win him another four years in the White House. At this point, does it much matter if he is acting purely out of political cynicism, with no element of personal prejudice? The rage he is nurturing and the pain he is causing are all too real. The damage he is doing will take years to undo.