George Bush's moral certitude stemming from his fundamentalist Christian views led him to believe that America was given a special dispensation from God to protect itself in any way possible, even perpetrating evil acts (torture, illegal confinement, etc.). His moral certitude was that, in a sense, he, George Bush, could do no wrong because God was on HIS side and on the side of America. Look at his recent press conference when he said mistakes were (only) "unfortunate."
He is leaving office believing he was always in the right and that history will absolve him. He really does believe that the Iraq War, a war of choice that slaughtered perhaps a half million Iraqis and displaced several million others, was justifiable.
I say that history has no timeframe on evil. I look forward to the day when historians, who have already judged the Bush Administration at the lowest possible rating, will help us understand that it was a last-gasp (even evil), episodic spasm of American Empire. Perhaps we can now live within a community of nations with real American leadership. The Planet has problems that cannot wait.