The Guardian - Hans Blix, whose judgment on these matters has stood the test of time better than many, summed it all up in an interview with a Danish newspaper this week. If the Americans stay in Iraq the country will not be stabilised, the former UN weapons inspection chief said. If they pull out, they risk leaving a civil war. All in all, Blix concluded, "Iraq is a pure failure".
National policy-making is shaped for a generation by traumatic international events. That's why, in our own case, the defiance of 1940 still casts lingering rays on the grandchildren of those who stood alone against Hitler. It's why the fateful delusions and humiliations of the Suez adventure still matter too, half a century on. And it is why, while acknowledging the possibility of the more benign longer view that Timothy Garton Ash properly outlined here on Thursday, the pure failure of Iraq will cast a long shadow over future British foreign policy too.
On both right and left this will be a cause for celebrations. Metaphorical Kalashnikovs will be fired into the air in the hot Hampstead night when Our Boys come home. But the members-only bars around Aldershot will echo to a bitter chorus of we-told-you-so too. You British have a word for it, the last German ambassador but one once said - you call it schadenfreude. Everyone will claim a slice, once the Iraq endgame is played out.
On the right, those who believe that Britain is always better-off unentangled with abroad will count this a notable scalp. Whether it's the EU, the UN or even the Special Relationship, they always prefer distance. When someone calls for Britain to take a lead, they count the spoons. Pessimists, they wanted nothing to do with Iraq, any more than with Rwanda, East Timor, Bosnia, Kosovo or Sierra Leone either. They will look the other way when we are invited to do our bit in Congo, Darfur or Gaza. They are the heirs of Walpole - 50,000 slain in Europe this year and not one Englishman - and, more uneasily, of Neville Chamberlain.
There will be a sense of vindication on the left too. In the world of my enemy's enemy is my friend, no disaster for American or British policy can ever be unwelcome. In this Manichean perspective, if Washington takes one view then they will always take the other, however grotesque the moral contortions it demands. Any American or British soldier's boot on foreign soil can only ever be imperialistic, and thus by definition wrong. British military defeats which the right, for whom the flag matters, mourns, bring comfort to the left, for whom the flag is the enemy.
Yet in an odd way there is a convergence between the nationalist right and the self-described internationalist left. Both of them believe, as the hideous Brezhnev always asserted when he was criticised for jailing writers and Jews, and as the Chinese government continues to argue today, that human rights matter less than nation states. Principles can be compromised. Frontiers can never be crossed.
In the face of a disaster like Iraq, absolutists are having a field day. It is easy to get swept along by the certainties of those who are always keen to prove that they are right about everything. But as the postmortems begin, still a tad prematurely at the moment it should be said, hang on to a reality. Very large numbers of us, perhaps a majority, are not members of either of these tribes. On some things some of us occasionally agree with one or other of the two extremes, but on most things we agree with neither entirely. Our voice needs to be heard too.
It seems to me that British foreign policy needs to recalibrate two large questions in the light of Iraq if this is to be done. The first is to reassert the continuing importance and relevance of international humanitarian intervention, by force if necessary. This will not be easy, because the reflex not to create "another Iraq" will rightly be strong. But it will be as true after this conflict as it was before it that the world cannot pass by on the other side when millions are oppressed by their own rulers, or their lives are destroyed by sweeping civil disorder. The Iraq war was emphatically not that kind of an intervention, which is why it should not be used to discredit interventionism in general, though of course it is a cautionary tale.
So the challenge is this: can the doctrine and weapons of interventionism be protected, honed and made effective so that oppressed and suffering people can be protected when their own governments are unwilling or unable to discharge the responsibility? In 2001 the International Commission on Intervention and State Sovereignty, sponsored by Canada, produced some robust thresholds: a grave breach of humanitarian law such as genocide or ethnic cleansing, the support of regional opinion, multilateral authorisation through the United Nations, military intervention a last resort. Britain may not be well placed, post-Iraq, to harness support for such an approach, but it should support those who promote it. We need to rescue the foreign policy of Robin Cook from the foreign policy of Tony Blair.
The second question is the relationship with the United States and Europe. This country has been hung out to dry internationally, sometimes with justice, sometimes unfairly, as a result of the follies of the Bush-Blair relationship. The tragedy of Blair's premiership is that, faced with a wholly new type of US administration attempting to deal with a largely new situation after 9/11, he applied so recklessly and naively the very lesson not to split from the Americans that British policymakers had drawn from Suez. In that sense the last great debacle ultimately begat the next one.
To some extent things will ease when the post-Blair chapter opens, and then perhaps ease further when the post-Bush one follows. But only if the next US administration changes markedly, which is far from certain, and then only if there is a new course for Britain to follow. Gerhard Schröder was wrong about many things in his career, but he is right to say in his diaries that Britain traded influence in Europe for closeness to Washington. That imbalance has to be changed. The post-Iraq situation cries out for a British foreign policy that is more fluently engaged in Europe. Yet in the wake of Iraq's pure failure, do not be surprised if instinctively Eurosceptic politicians like Gordon Brown or David Cameron opt for the quiet life and leave the problem for their successors to solve.