There's a lot of food for thought in William Saletan's Slate essay on the Bush press conference and this post on the same subject by Ezra Klein at Pandagon -- but I think the gist of what they're trying to say is presented most deftly by Ezra's partner, Jesse Taylor, who boils down Bush's apparent philosophy of governance to these two principles:
1.) It doesn't really matter what the right thing to do was, because Bush did it, is doing it, and will continue to do it, and all your objections do is distract from how right he is.
2.) The only accountability Bush has is towards himself. Did Bush do what Bush wanted to do? Yes. Therefore, there is no real problem.
That really is what Bush (and most of his advisors) seem to be saying all the time, isn't it?