Forget the clichés: whitewashes, establishment cover-ups et al. Sir John Chilcot is the right man to head the inquiry which opens for business this week. He has a lucid, forensic intelligence. He knows how government works. He also knows that this will be his momentum aere perennius; this is how he will be remembered. So he will want to produce a report that wins the respect of his peers: has them saying, "Well done, John" and meaning it.
In setting about his task, Sir John will face the same problem that confronts every historian: turning the horizontal into the vertical. Events are messy. They happen all at once, tumbling over each other like a litter of puppies. That is why the historian's work is never done. He has to shape chaos into sequence. Every attempt to impose such a structure has to be an over-simplification, which is why even the best books entitled, "The Causes Of The..." tend to be superseded every 50 years.
Even so, Ed Balls has not yet succeeded in suppressing either the teaching of history or mankind's curiosity about the past. Iraq arouses not only curiosity but controversy. As he attempts to transmute complexity into narrative, John Chilcot may come to rely on the three Cs: chronology, commentary and conclusions. Try to describe what happened: every so often, stand back and try to explain what it means. Then, finally, summarise and make judgments.
It is impossible to anticipate the inquiry's findings. But it may well conclude that from a British perspective, the whole affair is inseparable from the personality of Tony Blair. Iraq will be his legacy, because he was the only non-Conservative Prime Minister who could have taken Britain to war. In this, he displayed his strengths and his weaknesses: his high persuasive skills and his profound moral flaws.
Back in 2001-2, he and George Bush faced a similar difficulty. On both sides of the Atlantic, there was an irreconcilable divergence between those who supported the war and those who knew about Iraq. Almost all the experts were opposed to the invasion. Almost none of the warmongers knew anything about Iraq.
On each side of the Atlantic, the politicians resolved the dichotomy in the wrong way. Instead of seeing it as an opportunity for creative tension, they ignored one side of the argument. In the White House, the State Department's doubts were brushed aside as the wimpings of pointy-headed pinkos who ought to have been on one of Senator Joe McCarthy's lists. In London, Tony Blair was politer, but equally dismissive. A small number of officials, principally from an intelligence background – Richard Dearlove, John Scarlett – were mesmerised on to his sofa. The Foreign Office did not receive a hearing.
It did not help that Tony Blair had no confidence in Robin Cook, the then Foreign Secretary, or that Mr Cook's relations with his officials were often fraught. As a result of this, some conversations which ought to have taken place never happened. The first one would have been between the Foreign Secretary and his Permanent Under-Secretary:
Foreign Secretary: "Look, there is no point in continuing this discussion. The Prime Minister has decided on war, and that is that".
Permanent Under-Secretary: "Well, Foreign Secretary, if you really are bent on this, against the considered advice of everyone in this building, then here is what you should do, to have any chance of success".
Foreign Secretary: "Now you're talking. I want a paper on my desk by close of play tomorrow, setting out all of that – and I promise you I'll stand over the Prime Minister till he's read every word".
Indeed, the Foreign Secretary ought to have gone further. He should have pointed out to Mr Blair that the Americans who were in charge of Iraq – Dick Cheney, Donald Rumsfeld – were showing no interest in post-war nation building. That was dangerous, and it was time for us to get involved.
There would have been scope for this. The political reporting from the American embassy in London was of high quality. The President was aware that Tony Blair was taking political risks on his behalf. George Bush had a simple moral code: punish your enemies, show gratitude to your friends. Mr Blair had earned a lot of gratitude, yet he never asked for his reward. According to Christopher Meyer, who was our ambassador to the US at the time, Mr Blair did not even try to behave as an equal when he was in Washington. It was more a matter of an overawed, gawping country cousin.
If only he had said: "Now George, you lot have never been enthusiastic imperialists. We have. I bet some of my Foreign Office boys still have plumed pith helmets in their wardrobes. They'd all love to be a governor-general". Had Britain claimed a bigger role in the reconstruction, the idiocies of Paul Bremer's de-Baathisation and sacking the Iraqi army would have been avoided. Mr Bremer's decisions cost tens of thousands of Iraqi lives plus a few hundred allied ones. He held up progress for several embittered years and almost wrecked the mission. He may well be the worst public servant of all time. But if Tony Blair had asserted himself, he could have been saved from obloquy: Iraq, from much misery.
Mr Blair was assertive in other ways. The "45-minute speech" was one of the most effective of his Premiership. It was also one of the most dishonest. This had a serious long-term consequence; it undermined public confidence in the security services. But that was the trouble with Tony Blair. To him, the long-term was the next day's headlines.
That said, he did have a difficulty. There were three reasons for going to war with Saddam. The first was nuclear weapons. Saddam had been trying to acquire them for 20 years. We could not be certain that he was not about to succeed, and in his case, only certainty would do.
Second, the Iraqi dictator was ruling and ruining a country with a great heritage and equally formidable oil reserves. Iraq ought to have been the most successful large country in the Arab Middle East, offering its people decency, freedom and prosperity. Instead, it was a moral slum.
There were powerful reasons for arguing that all the routes to a better future for the region ran through Baghdad and that regime change was essential. That was the neo-Conservatives' view. Unfortunately, its strategic moral grandeur was not reinforced by tactical cunning: hence Mr Bremer. But on Iraq, Mr Blair was a fully paid-up neo-con, even sharing the tactical blindness. To be fair to him, he took that view because of its moral dimension.
Third, our most important ally was going to war. We too owed a debt of gratitude. Admittedly, Harold Wilson had stayed out of Vietnam. But by the time President Johnson was putting pressure on him, that war was foundering. Iraq seemed easier, and so it proved, despite Mr Bremer.
So there were three compelling reasons for war. Unfortunately for Mr Blair, two of them would have compelled most Labour MPs in the wrong direction. The lawyers would have insisted that regime change was illegal, and there would have been no gratitude to America under a Republican President. As a result, Mr Blair had to deceive his party: to spin and prevaricate his country to war.
It is by no means clear that he was wrong to do this. The destruction of Saddam was a noble cause, even if ineptly conducted. Did the end justify the means? That argument will run for at least the next 50 years, and the Chilcot report will make an important contribution. We can all await it with eager interest.