There’s plenty of evidence that he actually is very stupid, and that he may even have a learning disability. To be honest, once you accept the thought that he may be mildly retarded, you can’t unsee it. For example in the recent talk about rare earth minerals, it seems to me that Trump thinks rare earth is actually soil in the way he talks about it and it drives me nuts that the media doesn’t point this out:

“We’re looking to do a deal with Ukraine where they’re going to secure what we’re giving them with their rare earth and other things…They have great rare earth. And I want security of the rare earth, and they’re willing to do it."

But he makes up for it politically with great skill in appealing to people’s base emotions.