As a data point, Einstein was an incredibly stubborn man. So was Isaac
Newton. They're not exactly on my list of morons... (No, I don't have
links to loads of quotes opining that either one of them were stubborn
- it's just an observation I made after reading their biographies.)

I tend to think Bush is smarter than people give him credit for (well,
at least his detractors) and my basis for that is his dry wit. I find
him pretty humorous when he's throwing off-the-cuff remarks about. He
was quite witty during the 'town hall' debate with Gore in 2000. And
Bush really out-debated Gore who was being flagged as the brilliant
intellectual and debater.

Letting his opponents brand him as a moron has worked out well for him.
It's fairly difficult to warn people to be wary of someone you've
repeatedly called a moron.