WASHINGTON (AFP) - - US President George W. Bush's former chief spokesman charges in a harsh new book available Wednesday that the Iraq war was unnecessary and sold to the US public with a deceptive "propaganda campaign."

Released five months before November elections to decide Bush's successor, Scott McClellan's stunning memoir "What Happened" sent shockwaves through Washington and drew immediate and very personal attacks from former colleagues.

"As I have heard Bush say, only a wartime president is likely to achieve greatness," he writes in brutal book that Bush aides quickly branded a coarse betrayal. "In Iraq, Bush saw his opportunity to create a legacy of greatness."

But "war should only be waged when necessary, and the Iraq war was not necessary. Waging an unnecessary war is a grave mistake," McClellan, Bush's second of four press secretaries to date, says in the 341-page work.

The former aide writes that history and the US public seem to agree that the March 2003 invasion "was a serious strategic blunder" and accuses top Bush aides of sidelining inconvenient truths in their rush to sell the war.

The US president wanted to topple Saddam Hussein "primarily for the ambitious purpose of transforming the Middle East," but knew that the US public would never agree to send troops into harm's way for that purpose, he says.

So "the administration chose a different path -- not employing out-and-out deception, but shading the truth; downplaying the major reason for going to war and emphasizing a lesser motivation that could arguably be dealt with in other ways (such as intensified diplomatic pressure)," he said.

They pumped up the case for war with "innuendo and implication" while "quietly ignoring or disregarding" evidence against it.

The former spokesman also denounced the response to Hurricane Katrina and the outing of a covert CIA agent by top Bush aides, a scandal that embroiled McClellan and eventually led to his departure from the White House.

McClellan, a Texas native from a political family, went to work for Bush when the future president was the state's governor, was a spokesman for Bush's 2000 campaign, and served as deputy White House press secretary from January 2001 to July 2003, when he became the president's lead spokesman.

He resigned -- or was pushed out -- in April 2006 and left a month later, his credibility battered amid the scandal over the leak that Iraq war critic Joseph Wilson's wife, Valerie Plame Wilson, was a covert CIA agent.

McClellan accuses former top White House political strategist Karl Rove and I. Lewis "Scooter" Libby, once a top aide to Vice President Dick Cheney, of misleading him into publicly denying they played any role in the revelation.

Bush was also deceived, "but the top White House officials who knew the truth -- including Rove, Libby, and possibly Vice President Cheney -- allowed me, even encouraged me, to repeat a lie," says McClellan.

The usually cheerful former spokesman is equally savage regarding the White House's early "state of denial" in the face of the devastation from Katrina in August 2005 and the botched government response to the killer storm.

Current White House spokeswoman Dana Perino charged in a statement that McClellan, 40, had revealed himself as "disgruntled" and added, "It is sad -- this is not the Scott we knew."

The president "is puzzled, he doesn't recognize this as the Scott McClellan that he hired and confided in and worked with for so many years, and disappointed," she added.

Former colleagues also circled the wagons in response to published accounts from the memoir.

Rove and former Bush homeland security adviser Frances Townsend charged in separate yet strikingly similar television interviews that McClellan had raised no objections to strategies he now assails and was not present at key meetings to shape those policies.

McClellan also denounces the US media as "complicit enablers" of the Iraq war and self-flagellates: "I fell far short of living up to the kind of public servant I wanted to be."

"I still like and admire President Bush," he says.

"But he and his advisers confused the propaganda campaign with the high level of candor and honesty so fundamentally needed to build and then sustain public support during a time of war," he says.