Liberal Oasis cracks the mystery behind the joint appearance of Bush and Cheney before the 9/11 commission (actually, since they came to the Oval Office, it was more like they were appearing before them).
Perhaps (and this is just speculation) the whole idea of the joint appearance was not to protect Bush.
But to protect Cheney.
Perhaps they reasoned the president, especially in the Oval Office setting, would be a magnet for questions.
Which would steer questions away from Cheney, and leave unexplored his inactive terror task force, and his actions on 9/11 itself.
What a subtly brilliant idea. Cheney really is the more interesting character in this whole dynamic. But by having them appear jointly, naturally the commission members are going to focus the majority of their questions towards Bush.