Intelligence is like pornography, I recognize it when I see it.
Reagan wasn't too bright, but he was a charismatic speaker, probably from his training as an actor and broadcaster. The Senior Bush was a poor to average speaker, but he was an intelligent man as evidenced by his successes in both government service and business. The current president is neither a good speaker nor very intelligent. Jeb Bush, is both highly intelligent and extremely articulate, I was worried about him but I don't think he'll be a problem now.