Its easy to call him stupid, to point out how self serving/narcissistic he is or how much a bully/authoritarian. And I find each of these descriptions to be compelling, but then there are descriptions that make him out to be somewhat of a Svengali, or at least suggest a he is trying to destroy our country in pursuit of his own Banana Republic-like state—something which would imply some smarts to do effectively. I feel like we really need a sort of grand theory of Trump from which to work.
To start with I would posit that Trump is a fairly disciplined marketer. It takes some skill to pick out a frame and some discipline to repeat it as much as he does. He is so effective at this that the left helps him by parroting his frame in a weak attempt to ridicule him.
His leadership style is authoritarian-seeming and hands-on-like. That is to say he reacts as if he is authoritarian. He seems to be fairly hands-on, drafting memos for his underlings (at least those in the family) to try to bamboozle us. But he doesn’t appear to have the attention span or physical energy to do this on the scale of the enterprise either his business or his position as POTUS would demand of a hands-on authoritarian would be Banana Republican. In fact he seems interested in pontificating—griping really—more than actually leading. So he might really be described as Laissez-faire with the authoritarian flare being a marketing gimmick.
That he seems to be a high functioning narcissist seems obvious at this point and is an important point to knowing how to get into his head. But high functioning only points out that he can act acceptably normal while preening. His intelligence level is limited by the fact that he is a narcissist. That is to say that he thinks he knows and so looks no further than the mirror for advice and understanding. At this level and at this time in our body politic, it is unnecessary for someone of the repugnicon mind-set to be, or to look, intelligent, even though many are. If you don’t act nearly Ghomert dumb, you are going nowhere fast. I don’t know if Trump is Ghomert dumb (or if Ghomert is Trump dumb), but I suspect he hovers near by since he cannot question his own supremacy.
So that's all I have in general way of a grand theory—I wouldn’t know how to come up with one anyway. But for me this addresses the problems with the dueling descriptions of Trump fairly satisfactorily. It allows for some level of intelligence but not the type that can plan the destruction of a society to take it over as a dictator. More of the type that could destroy it by bumbling around.