David Roberts, writing for Vox, says that trying to understand what Donald Trump really believes is a category error:
The question presumes that Trump has beliefs, "views" that reflect his assessment of the facts, "positions" that remain stable over time, woven into some sort of coherent worldview. There is no evidence that Trump has such things. That is not how he uses language.
When he utters words, his primary intent is not to say something, to describe a set of facts in the world; his primary intent is to do something, i.e., to position himself in a social hierarchy. This essential distinction explains why Trump has so flummoxed the media and its fact-checkers; it’s as though they are critiquing the color choices of someone who is colorblind.
What he’s doing is trying to establish dominance — to win, in his words. That’s what he uses words for. That’s how he sees every interaction in which he is involved. He is attuned only to what the words are doing, whether they are winning or losing, not to what they mean.
This point helps explain why Trump cannot ever admit a mistake or an error. He can only process accusations — of dishonesty, of cruelty — as social gambits, not as factual claims. To him, the demand that he apologize or admit error is nothing more than a dominance play. Apologizing is losing.
That the party of Lincoln nominated this person for president will go down in history as the turning point in American civilization, I think.