BRITAIN/Analysis: It is the Prime Minister's Iraqi campaign which historians will see as transforming the long-term assessment of the Blair premiership.
That transformation, moreover, can be traced back to the prior "war" on terror. For in a way not yet fully grasped in Britain, the events of September 11th changed the world for Tony Blair, almost as profoundly as they shaped the Presidency of George W. Bush.
The Blair-Bush coalition has come to represent the real "axis of evil" for much of the British left. Never reconciled to Mr Bush's victory over Al Gore, for much of "New Labour", too, only the scale of the death and suffering inflicted on that fateful day allowed them to tolerate the war against the Taliban.
But war against Saddam Hussein, they warned, would be a step too far. It would be a foolhardy adventure fuelled by ambition to control Iraqi oil, dictated by a dangerous new breed of pro-Israeli neo-conservatives in Washington, driven by the President's personal need to complete his father's "unfinished business" in the Gulf, which would provoke backlash in the Arab world and recruit another generation to the ranks of al-Qaeda.
Archbishops led the chorus of concern that such a war would be illegal and immoral without the sanction of the United Nations, although it was never clear why churchmen in particular should seek moral justification from President Chirac or Russia's President Putin. Predictions of catastrophe ahead invoked memories of Suez and Vietnam.
Clare Short branded Mr Blair reckless of his office, his government and his place in history, and vowed she would resign without a UN mandate both for military action and for the subsequent reconstruction of Iraq.
Serious commentators debated suggestions Mr Blair had become, in the literal sense, "unhinged" and accepted every backbench dissident prediction that the Prime Minister could become the first British casualty of the conflict.
At its end, meanwhile, the "Father" of the Commons, Tam Dalyell, suggested his leader "should be branded as a war criminal and sent to The Hague." Mr Blair savoured the moment in the Commons on Wednesday when a Labour backbencher, David Winnick, volunteered his colleague, George Galloway - dubbed the MP for Baghdad Central - to accept the formal surrender of the Iraqi regime.
As the warm murmur of Labour approval enveloped him the Prime Minister might have found it hard to identify all 139 of those backbenchers who had staged the largest rebellion in parliamentary history just weeks before.
Or to believe that barely a week into battle Robin Cook had demanded he bring the troops home before more of them died in an unnecessary and badly planned war.
As for Tony Benn's notorious invitation to President Saddam to send a message to the peace movements of the world, well, that plainly belonged in another age.
If the planned moment of Mr Galloway's liberation from the Labour Party is at hand, the continued captivity of others may make for a more gruesome spectacle. Mr Cook can forget any notion of inheriting the crown, or performing as king-maker, come the eventual battle for the succession.
As for Ms Short? She was at it again yesterday, unable to say with hindsight that the war had been justified by the extraordinary scenes in Baghdad, even though she had served as a member of the war cabinet.
Already the Westminster gossip is of a summer reshuffle in which Mr Blair will reward the loyal. And, as one government insider put it yesterday, "This certainly gives a whole new meaning to the phrase 'semi-detached'. I fear Clare is in much the same position as Mo Mowlam after she refused to leave Northern Ireland."
For the moment we can believe Mr Blair's thoughts are on higher things. Potentially perilous moments still lie ahead for the allied forces in Iraq before the peace is secured and final victory proclaimed. Thereafter Mr Blair with President Bush will calculate the altered strategic balance they have forced in the Middle East as they push their proposals for an Israeli-Palestinian settlement. Then there is always Europe.
Despite the challenges for the EU, NATO and UN, Mr Blair emerges from this with his own world affirmed. The message from Hillsborough was that the "special relationship" is deeper than ever.
Yet Mr Blair must also prevail over Mr Chirac and provide the transatlantic bridge from Europe. As the Conservatives join in the applause, their darkest fear must be that a triumphant Mr Blair will seek to fulfil Britain's "destiny" by winning a referendum on the euro before next year is out.