You have a good point there--and I think part of the reason so many people voted for Bush is because they saw Gore as too much of an intellectual, which scares a lot of people for some reason. Can't say I blame them though, I always found it odd how he never used contractions...
Though I don't believe Bush is purposefully coming off as stupid, I think he really is pretty dumb. Making mistakes pronouncing simple words like "underestimated" will not make you seem pleasently average like so many Americans identify with, it will make you seem like a dumbass.