It has taken more than three years, the loss of tens of thousands of Iraqi and US lives, and US$200 billion - all to achieve a chaos verging on open civil war.
But finally the neo-conservatives who sold the United States on this disastrous war are starting to utter three small words - we were wrong.
The about-face has spread across the conservative spectrum, from William Buckley, venerable editor of The National Review to Andrew Sullivan, once editor of the New Republic.
The patrician conservative columnist George Will now concludes that all three members of the original "axis of evil" - Iran, North Korea and Iraq - "are more dangerous than when that term was coined in 2002".
Neither Buckley nor Sullivan concedes that the decision to topple Saddam was intrinsically wrong.
But "the challenge required more than [President George W. Bush's] deployable resources", the former sadly recognises. "The American objective in Iraq has failed."
For Sullivan, today's mess is above all a testament to American over-confidence and false assumptions, born of arrogance and naivete. But he, too, asserts, in a column in Time magazine, that all may not be lost.
Of all the critiques, however, the most profound is that of Francis Fukuyama, in his forthcoming book America at the Crossroads. Its subtitle is Democracy, Power and the Neo-Conservative Legacy - and that legacy, he argues, is fatally poisoned.
This is apostasy on a grand scale. Fukuyama, after all, was the most prominent intellectual who signed the 1997 "Project for the New American Century", the founding manifesto of neo-conservatism drawn up by William Kristol, editor of the Weekly Standard, the house journal of the neo-conservative movement.
The PNAC aimed to cement for all time America's triumph in the Cold War, by increasing defence spending, challenging hostile regimes and promoting freedom and democracy.
Its goal was "an international order friendly to our security, prosperity and values". The war on Iraq was the theory's test. And after Iraq, why not Syria, Iran and anyone else who stood in Washington's way?
That doctrine, Fukuyama acknowledges, has been a tragic conceit.
Fukuyama, of course, once claimed in his The End of History and the Last Man, that the world was on a glide-path to liberal, free-market democracy. But he also pointed out that it should have been left to its own pace.
The neo-cons' first error was impatience. The second was a belief that an all-powerful US would be trusted with "benevolent hegemony".
The third was the overstatement of the threat posed by radical Islam to justify the doctrine of preventive war.
Finally, there was the contradiction between the neo-cons' aversion to Government meddling at home and their childlike faith in their ability to impose massive social engineering in foreign and utterly unfamiliar states.
Some, however, are unswayed. Kristol accuses Fukuyama of losing his nerve - of wanting to "let large parts of the world go to hell in a hand basket, hoping the hand basket won't blow up in our faces" in the Standard.
Christopher Hitchens, the one-time Trotskyist turned neo-con, derides Fukuyama for "conceding to the fanatics and beheaders the claim that they are a response to American blunders and excesses".
The fact remains that the Bush policymakers who signed the PNAC are mostly gone. Paul Wolfowitz, the war's most starry-eyed promoter, moved to the World Bank, silent about the mess he did so much to create.
Richard Perle, leader of the hawks at the American Enterprise Institute, has vanished from the scene.
Lewis Libby has stepped down as Vice-President Dick Cheney's chief of staff, to focus on staying out of jail. This week US Ambassador to Iraq Zalmay Khalilzad - Afghan born and the one original neo-con who had the region in his blood - admitted Iraq had opened "a Pandora's box".
Those who are left - primarily Cheney and Defence Secretary Donald Rumsfield - are not so much neo-cons as advancers of US national interests, whatever it may take.
Condoleezza Rice, never a signed-up member but still sympathetic - metamorphosed into a pragmatist.
It is on Bush's lips the neo-cons survive - in the commitment to freedom and democracy that he proclaims daily. But his oratory cannot obscure the irony of the Iraq adventure.
Neo-conservatism espoused the vastness of US power - but it has succeeded only in exposing its limits.
Fukuyama now wants to temper the doctrine with an acceptance that some things are not easy to change, and that the US must cut its cloth accordingly. A term for this might be neo-realism.