Eleanor Clift gets it exactly right in The Wizard of Oz Letter, (thanks to Smirking Chimp for the link)
What Cheney and the tight circle around Bush are protecting is the myth they have created since 9/11 of a war president astride the world stage. Anybody who punctures that imagery is destroyed. Richard Clarke is only the latest in a series of insiders who have pulled back the curtain. At the center is an incurious president who is so inarticulate that he can't be left on his own to make a sustained argument on behalf of his policies without falling back on rehearsed talking points and sound bites.She even compares George "if I only had a brain" Bush to Reagan, who testified while suffering from Alzheimer's disease and allowed his testimony to be videotaped.
Who knew we'd hit the Wizard of Oz trifecta? No brain, no heart, and no courage.