Colbert King describes Il Trumpe to a T (boldface mine):

Let’s cut out all the mealy-mouthed reporting about who Trump is and what he is up to.

America has in Trump the kind of president it would have had if South Carolina segregationist Strom Thurmond had won when he ran on the Dixiecrat ticket in 1948. There wouldn’t have been a dime’s worth of difference between a Trump administration and the administration of Alabama race-baiter George Wallace had he captured the presidential contest in 1968.

Racism, perhaps along cruelty, are the two ideologies Trump truly holds dear. His first noticeable activity as a businessman was to discriminate against black renters. Moreover, he seems completely incapable of toning down his racism to any significant degree (or for a considerable length of time). The horrifying irony is that, if he were to tone down the racism–he could still do all the racisms on the policy side, just more quietly–he probably would win re-election, with the Obama economy still trundling along (arguably, he might not have won without his overt racism).

It’s just who he is. It’s his one true ideology.