Ben Carson is a good illustration of how extremely intelligent people are often even more clueless and more worthless in areas outside their expertise than the hoi polloi, as they overestimate their competence and knowledge greatly.
I call this “engineeritis” because it is most common in fields like engineering and physics, but is present in every arena where overly-intelligent people cluster.
The smart on paper candidates this year are just suffering from some Dunning-Kruger? That makes everything better! How much of that is Dunning Kruger and how much of that is “telling people (primary voters) what they’d like to hear”? Many people like to hear actively stupid things voiced in public. If I’m making easy money going around the country and talking to stupid people, I’m definitely going to say that Jesus and his dinosaur friend Pete are at the gun range in heaven and will come back down to save the Second Amendment from the earth. Just saying.
Ben Carson probably doesn’t believe all he has been spouting, but have you seen his house? Portrait (and a bad one) of him hanging out with Jesus and the like.
He might not be quite as bad as his supporters, but he fits right in with them, without having to pretend like some of the candidates.