Many observers, both Bush insiders and critics of the administration, wonder why McClellan waited until now to voice these concerns.
"There is something about this book that just doesn't make any sense," Ari Fleischer, McClellan's former boss and predecessor, said in a statement. "For two and a half years Scott and I worked shoulder to shoulder at the White House. ... Not once did Scott approach me -- privately or publicly -- to discuss any misgivings he had about the war in Iraq or the manner in which the White House made the case for war.
"If Scott had such deep misgivings, he should not have accepted the press secretary position, as a matter of principle," Fleischer said.
McClellan writes that he was driven to write the book in an effort to tell the truth and be, metaphorically, set free.
He has, no doubt, burned bridges, but his decision to tell his truth may be what he was ultimately after, said ABC News consultant Matt Dowd, a former Bush advisor who parted with the President over Iraq.
"At some point you have to ask, what are you most loyal to? Are you loyal to a person? To the administration? To your own sense of truth?" Dowd said. "When there is a conflict between your loyalty to a person and your loyalty to the truth, you have to make a decision."