Mark Crispin Miller (author of The Bush Dyslexicon on our President:
An Interview with Mark Crispin Miller - Democratic Underground
Bush is no Dan Quayle, who is a genuinely stupid man, but something else entirely. On the one hand, he is every bit as ignorant as he appears—that is no act, although such emptiness of head is often something of a plus for him with quite a few of his supporters. So while Bush's ignorance is real, his knack for flaunting it as if it were a sign that he's just folks is pretty artful. And as Bush knows very little about anything (except baseball), neither is he capable of reasoning in any complicated way.

Despite those limitations, however, Bush is not an idiot—and it's a grave mistake to write him off as one. He has very sharp political instincts (unlike the hapless Quayle). To laugh at him for his stupidity is actually to do him a big favor, since it helps him with that pose of commonness. (It helps him here, in the United States, with that plurality who voted for him. It doesn't do him any good at all beyond our borders.)

Bush's problem—or rather, our problem with Bush—is not so much that he's an idiot as that he is contemptuous of thought, complexity, ambiguity. He's proud of his closed mind. That makes him far more dangerous than he'd be if he were merely dim.