There are two schools of thought forming inside regarding Scott McClellan's bombshell book: Either he should have resigned then, or he's been coopted by nefarious forces (read: liberal publishers).
The first school of thought is explicated by my U.S. News colleague John Mashek in his blog today. Mashek runs through the list of people who have resigned in protest over the years, starting with Elliot Richardson and William Ruckelshaus during Watergate (he forgot Tony Lake resigning from that administration over invading Cambodia) and running right up through Peter Edelman quitting Clinton over the welfare overhaul.
Resignation certainly has a distinguished history and a powerful case. But ... while I'm only about 50 pages into the volume, I actually find McClellan's story -- that the tone of the book evolved in the writing and as he decompressed from his White House experience -- entirely plausible. Have you ever been in a situation where you behave in a certain way and then, with the passage of both time and the pressures of the moment, you look back and wonder at your choices? Looking back budding problems are clear but you just didn't see them, acknowledge them, what have you?
Hindsight is, as they say, 20-20 and while it might have been laudable for McClellan to quit, that he has now written a book acknowledging the administration's tragic blunders doesn't mean that he had the same frame of mind then. (I can tell you from personal experience that tones, ideas and whole books can change as they go.)
In fact to say that McClellan can't have changed his mind between now and then is to insist that he be as mentally unswerving as Bush.
As for the White House's "That doesn't sound like the Scott we know..." talking points -- with the implication being that his book was commandeered by a liberal ghostwriter or editor, McClellan's critics miss the point: Whose name is on the book? Whether the former White House press secretary personally crafted each phrase is less relevant than that they are his ideas, that he has put his one name on it and that he stands behind them. (In that regard, the situation is much the same as with speechwriters.)