Linguist Mark Liberman, no Bush supporter, has some surprising negative remarks about the campaign to make President Bush look like an dunce through overexamining his speech to find any possible regional accent, slip of the tongue, or nonstandard use, then calling it a Bushism. (I remember when they did the same sort of thing to Dan Quayle while ignoring everything positive that he did. He may have been the hardest-working and effective Vice-President of the entire 20th Century, but the media, and I'm using this term loosely, successfully ruined his political future through their twisted quest to portray him as an idiot.)
From what Liberman says, I get the impression that most of these Bushisms are as unreliable as a hung-over college student's memories of the previous night out on the town. The ones they do find are not surprising when people are poring over everything he says to find such things. He gives a good example of a reporter presenting Bushisms himself but with three downright embarassing misspellings (e.g. "agregious") that if Bush were to submit to a newspaper would be called Bushisms. So it's not just overly picky for the political purpose of undermining the man's public image. It's outright hypocrisy. Everyone does this.
Liberman: "You can make any public figure sound like a boob, if you record everything he says and set hundreds of hostile observers to combing the transcripts for disfluencies, malapropisms, word formation errors and examples of non-standard pronunciation or usage. It's even easier if the critics use anecdotes based on the perceptions and verbal memories of equally hostile listeners. And the whole thing has crossed some kind of line when you can make the AP wire by citing him for using a widely accepted pronunciation..."
This is more of a sign that Bush really is in many ways more like the average American than those who think of him merely as a jingoistic child of privilege (as a friend of mine recently described him) would want to think.