Last Wednesday newly released documents revealed evidence that, in a less degraded political culture, would have produced a scandal. The Chilcot inquiry heard that the then attorney general, the government's chief legal adviser, explicitly warned Tony Blair that an invasion without further United Nations approval would be illegal.
"In view of your meeting with President Bush, I thought you might wish to know where I stand on the question of whether a further decision of the UN security council is legally required in order to authorise the use of force against Iraq. My view remains that a further [UN] decision is required," wrote Lord Goldsmith. As if further clarification were necessary, a handwritten note, assumed to be written by Blair's chief foreign policy adviser, David Manning, warned: "Clear advice from attorney on need for further resolution."
Unable to say he hadn't been told, Blair instead behaved as though English had just become a foreign language. "I just don't understand this," he wrote in the margins. The very next day he flew to Washington and told George Bush he was "solidly with the president" regardless of what the UN did. Put bluntly, it is irrefutable proof that the British prime minister was willing to flout international law.
A few hours after the document's release, across the Thames in a sweaty room in Lambeth, the Labour leadership contenders went through their paces. Each argued that under their guidance the next Labour government would listen so that it could learn, and inspire so that it could lead. Each paid homage to fairness, equality and empowerment while struggling to differentiate themselves. The lack of ventilation in the room and engagement from the stage induced a strange compulsive torpor. You couldn't look away because there was nowhere else to look, but you couldn't listen because they spoke in a parliamentary patois that mixed English with some obscure institutional inflection. It was as though Charlie Brown's teacher were standing for leader of the opposition, her words turning to an unintelligible drone by the time they reached the back of the hall.
You would think there might have been a connection between these two events. The inquiry marked another crucial moment in an investigation that is revealing the true extent of duplicity and criminality within a Labour government that led up to an unpopular and calamitous war; the hustings are a bid by members of that self-same party to renew its credibility and purpose after a crushing defeat at the polls.
But in two fetid hours, Iraq never came up. Not a single candidate uttered its name from the podium and not a single question about it came from the floor. The whole evening was like a cross between Seinfeld and Fawlty Towers – a show about nothing in which nobody mentioned the war.
That many of us who opposed the war and still oppose the occupation find this problematic is no surprise. It was the most defining personal political choice of the decade and, ethically speaking, not a remotely tough call. The fact that it was illegal adds judicial finality to a moment of moral clarity; but even within the law, it would have been wrong. The ramifications were not only predictable but predicted. Hundreds of thousands murdered, even more displaced, the unleashing of sectarian violence. Getting that wrong speaks to a major, murderous error of judgment.
True, it had come up in previous leadership debates, and will undoubtedly come up again. But the frontrunner, David Miliband, would like us all to move on and, if Wednesday is anything to go by, seems to be getting his way.
"You've punished us enough about Iraq," he told Labour voters before the election. "The purpose of these elections is how we build a better tomorrow," he told the Telegraph at the weekend. "Not how we debate a better yesterday."
This is a curious piece of logic. The best indication of what people will do with power is to look at what they did when they had it. For what we do tomorrow is inevitably bound up with what we did yesterday. People who made grievous errors yesterday shouldn't be trusted to make intelligent decisions tomorrow unless they are able to account for their mistakes today. In truth they haven't been punished even nearly enough. They should be in jail.
The attempt to paint those who still raise these arguments as obsessives mired in paradigms past misses both the point and an opportunity. The point is that the occupation is still going on, and the other war to which it is inextricably bound, in Afghanistan, is still going wrong. "The essential characteristic of a nation is that all its individuals must have many things in common," wrote the 19th-century French philosopher Ernest Renan. "And must have forgotten many things as well." But in the past people had the decency to at least wait until things had finished happening before they started forgetting them.
The opportunity Iraq provides is to understand what went wrong in government as a means to restoring trust within the party and the country, which would be indispensable for any serious effort to commence an ideological, moral and political renewal. There are, without doubt, many other vital issues. But there are few that encapsulate the issues Labour needs to grapple with, whether you supported the war or not.
Among other things, Iraq raises the following questions: What does a Labour government do when it is presented with facts that contradict its convictions? How does it respond when most of the country demands that it change course? When have the candidates put their consciences before their careers? What internal democratic mechanisms exist within the Labour party to check the will of a determined leader? How does it deal with dissenters and dissent within its own ranks? How would a Labour government respond when it has clearly made a mistake?
It is not the only prism through which Labour's period in office can or even should be examined; but it is the only one that brings together those fundamental questions in one issue.
In an ideologically crowded field, it also provides a rare distinction between the candidates. There's only so long they can ignore this elephant in the room before it takes a dump on the carpet. Andy Burnham is proud to have supported it; Diane Abbott is proud she didn't; David Miliband regrets supporting it and even having the issue raised; Ed Miliband and Ed Balls weren't in parliament for the vote and, while neither spoke out against it, now say it was wrong. But the other reason why it is important is because it is unavoidable.
When giving examples of why Labour should listen more, a few candidates mentioned the 10p tax rate, an important subject to be sure but not the one that produced the largest demonstration in the history of the country or killed anybody. When asked about whether Labour had got the balance right between civil liberties and protecting the country from terrorism, David Miliband recalled sitting in Downing Street on 7 July 2005 and asking himself: "Could we have done anything to prevent this?" Well they could have not invaded Iraq, which every investigation has shown was the primary thing that made Britain a target.
It is precisely because the issue is so toxic that the poison must be drawn. For only then can Labour be dragged from its sick bed and stand for something more than just elections.