The sad part of the 9/11 Commission is that its purpose is primarily political, in a political year. Certainly neither Bush nor Clinton wanted 9/11 or anything similar to happen. They both acted in the manner they believed appropriate, based on the information they received. Neither knowingly ignored any of the warnings we now read about with the help of 20/20 hindsight.
Commissions with their windbag politicians are, to paraphrase Shakespeare, full of sound and fury, and signify nothing. The people who perished on 9/11 deserve better.