In this political capital where loyalty is the coin of the realm and biting the hand that has fed you is almost unheard of, the confessional new book by former Bush White House press secretary Scott McClellan is a notable rarity.

McClellan always was seen in the White House as personally loyal to President Bush, who had brought him to Washington from Texas, and as a press functionary who would not tell a reporter if his coat was on fire. Perhaps that was because he was perceived as being kept out of the loop on anything important.

He was a master of the noncommittal and the evasive, and one of the reasons for his departure in 2006 was that he was seen as a poor salesman of administration policy. His successor, television and radio smoothie Tony Snow, was all that McClellan was not.

His tell-all book is a most welcome one because it appears to confirm from the inside what most Americans have come to recognize about the war in Iraq — that it was deceptively sold to them by a president who intended all along to take that calamitous initiative.

McClellan writes that President Bush "was set on regime change from the earliest days of his decision to confront Iraq" and "managed the crisis in a way that almost guaranteed that the use of force would become the only feasible option."

But the invasion was not, by any reasonable assessment at the time, the only "feasible option," except for a president who had made up his mind to get rid of Saddam Hussein. The international inspectors who had been unable to find weapons of mass destruction in Iraq were poised to go back in to look again when Bush's invasion precluded the possibility.

McClellan in his book says that in the summer of 2002 Bush aides "had outlined a strategy for carefully orchestrating the coming (congressional) campaign to aggressively sell the war," as part of a White House that treated governing as a "permanent campaign." As a member of the administration's communications apparatus as a press deputy at the time, McClellan dutifully kept this fact to himself, if indeed he knew it then.

McClellan observes now that "what I do know is that war should only be waged when necessary, and the Iraq war was not necessary." The comment, beyond being a damaging criticism of his old boss, is not helpful to John McCain, the prospective presidential nominee of McClellan's party, and a gift to Barack Obama, his likely Democratic opponent in November.

Former White House colleagues of McClellan have responded to the book with a combination of shock and a sense of betrayal. That's not surprising, since many of them were themselves involved in the deceptive selling of the war and continue to cling to its rationales.

Among the most singed by the book is Karl Rove, Bush's former White House political guru, who continues to be a target of congressional Democrats. McClellan writes now that he was misled about Rove's involvement in the "outing" of CIA agent Valerie Plame Wilson.

When McClellan told reporters in October 2003 that Rove and vice presidential aide Lewis "Scooter" Libby "assured me they were not involved in this," he writes, "there was only one problem. What I'd said wasn't true."

The confessional book by one of the strongest Bush loyalists comes at a time when the administration is showing all the strains of a lame-duck presidency.

Key officials are deserting the ship for opportunities in the private sector while those opportunities remain. On Capitol Hill, Republican legislators are demonstrating increasing willingness to break with Bush on domestic issues, while loyally saying little on the unpopular war.

Because Scott McClellan essentially was a bit player in the Bush administration, the damage his book may have dealt to a president heading for the exit as a lame duck, to the Republican Party and to its chances in November, will probably be fleeting. But Bush needed his old loyalist's confessions right now like he needed a poke in the eye with a sharp stick.

Jules Witcover's latest book, on the Nixon-Agnew relationship, "Very Strange Bedfellows," has just been published by Public Affairs Press. Reach him at juleswitcover@earthlink.net.