Another explanation of Bush behavior can be found in this excellent analysis by Julian Sanchez. I think he's got it right:  for W, it's all about the nobility of one's intentions, not the consquences, especially the unintended consequences, of one's actions.  Money quote:

This would also go a long way toward explaining Bush's visceral reaction to criticism. If one is in the habit of separating intent from outcome, not every mistake is shameful. Things can turn out badly even though one behaved as well as could be expected. When they're inextricably linked, however, every allegation of error rings like the accusatory cop-out of the failed revival healer: "It only works if your faith is strong." To accuse Bush of having made a bad decision is, if this is indeed his mind-set, in effect to call him a bad person, to question the quality of his heart no less than his judgment. Admitting error, acknowledging that things haven't panned out, becomes impossible.

Very good piece.