Trump Criminal Trials, page-12330

I don't he's particularly smart. He's ruthless.

No empathy , no social or moral filters that would stop a normal decent person doing what he would say or do.

He views those filters or lines in the sand that decent people have as weakness and exploits them. You're either blowing warm air up his **** or you are the enemy as many of his former aides and colleagues have found.

He has no qualms about manipulating people or screwing them. Most people would not do that.
But because he does those things, he has become successful and gives the appearance of being clever.

I dont think he's particularly stupid either, but his colossal, impenetrable ego and narcissism inhibit good judgement. But that ego and narcissism combined with his sociopathic personality make him a very dangerous person.