Digby has a post up about the two faces of Bush
an excerpt, but please go and read it all:

“George W. Bush is a man of two faces – a public image of manly strength and a private reality of childish weakness. His verbal miscues and malapropisms are the natural consequences of a man struggling with internal contradictions and a lack of self-knowledge. He can’t keep track of what he is supposed to think and say in public.”

I think Digby has it about right. I’ve long thought that the real reason Bush can’t answer questions is because he only knows the sound bites he’s told to say. He has no depth of understanding of any of his administration’s policies. He is at the core a very weak man. The only thing I’d add is that when someone cannot reconcile his self-image with reality, then there is apt to be a serious breakdown of all reality looming. Just my opinion, but I think we’ve seen what happens when George Bush’s reality is questioned.