What do we call someone who dismisses reality?

A fool? A nut? Megalomaniac? Mr. President? Reading the following paragraph from the New York Times' review of Dead Certain - Robert Draper - The Terror Presidency - Jack Goldsmith brought to my mind the question and those answers.

"“Dead Certain,” the title, conveys one of those characteristics. Bush knows he is right. When facts turn out to get in the way, he brushes them off. When “Mission Accomplished” turned sour in Iraq, when various supposed bench marks of success did not stop the bloodshed, the president remained utterly confident of victory. He was sure, Draper writes, that “history would acquit him.”"

And a dreadful feeling that we have been really screwed.