It doesn't matter what you ask him. He truly believes what he's doing is right and will not listen to anyone else.
If given one chance to ask him a question I'd let everything get set up, the Secret Service would be present, cameras everywhere, Bush's writers have scripted responses for possible questions I might ask, and people are all standing around watching. I sit down in the chair across from him, look at the crowd in the room busy snapping pictures and whispering among themselves, I'd look Bush in the eye, and then stand up and walk out.