Leading article: Unrepentant and assured, Mr Blair sees nothing to learn

For all the keen anticipation of Tony Blair's appearance before the Iraq Inquiry, few can realistically have expected that he would express either second thoughts or regret. So there can be little disappointment on that score. This was always likely to be a small print rather than a big picture occasion.

And yet the pictures were telling. This was the first time that the former Prime Minister had been called to explain himself outside Parliament and in public on what has been the most divisive policy issue for at least a generation. He had testified to previous inquiries, but behind closed doors or in writing. The questioning was largely on his terms.

Yesterday Mr Blair was required to explain in detail his overall thinking and motivation as events unfolded, and to do so as the cameras rolled and the proceedings were relayed across the land. As previous witnesses to the inquiry have stressed (for their own reasons), he was the man running the country at the time, the man who took the decisions, the man with whom the buck came to stop. His usual unapologetic self Mr Blair might have been, but there were moments when even he seemed disconcerted.

He was not exactly in the dock. But he was at times on the defensive. The last 15 minutes, in which statistics for casualties, infant mortality and living standards were tetchily traded across the table to support or demolish the most basic argument – was Iraq now a better place? – provided a real echo of the angry debate that has consumed Britain since the shadow of this war first fell across our horizon. The exchange also provoked the only emotional intervention from the public gallery. This is not a national quarrel that is going to be settled soon.

We could have wished for tougher questioning. Sir Roderic Lyne, who has emerged as the canny attack dog of this inquiry, seemed hesitant about skewering the former prime minister, even when the opportunity presented itself. If anything, it was the scholarly Sir Lawrence Freedman who seemed to get under his skin, persisting with the finer points of detail that Mr Blair is in the habit of skirting so adroitly.

Yet this was no waste of a day: not for the panel, nor for the probably global audience, nor, he will probably judge, for Mr Blair. The questioning fell naturally into two parts: before and after the war. He emerged a good deal more convincing from the first part than the second.

On the decision to prepare for war even before the United Nations process was exhausted, Mr Blair defended himself robustly. There was no secret deal with George Bush at the president's Crawford ranch. On the intelligence, there was no effort to mislead either Parliament or the British public. There was rather, Mr Blair said, a reassessment of the risk posed by Saddam Hussein's Iraq in the wake of the attacks of 11 September 2001. His decision to take on Saddam Hussein, he said, reflected his own firm belief, not that there was any direct connection between al-Qa'ida and Iraq, but because of the risks that Iraq, not disarmed, might pose in future. It was a matter of judgement.

This defence, as was doubtless intended, negates many of the objections that have been made, whether on the legality of the war or the flawed intelligence. Judgement trumps all. But it also exposes Mr Blair to a graver charge. If joining the US invasion was simply a matter of judgement, it was a judgement that was catastrophically wrong, as this newspaper has always argued, giving rise to a foreign policy mistake on a par with Suez. Mr Blair might have believed he was protecting Britain's security, but the result has arguably been the reverse.

On the disastrous aftermath of the invasion, Mr Blair was strikingly less willing to take responsibility. It was as if the whole mismanaged occupation was nothing to do with him. There had, he repeated, been detailed preparations, but the reality had turned out differently. Time and again, he parried suggestions that other scenarios could and should have been considered.

Most disturbing, however, was Mr Blair's interpretation of the wider context. In his view, the post-war violence in Iraq was all the fault of outside meddling by Iran and al-Qa'ida – a potential alliance, he warned, without discernible evidence – that vindicated the decision to take on Iraq and now obliged the West to stand up to Iran. It had nothing to do with the destabilisation that is the entirely foreseeable result of invading someone else's land.

The task of the Iraq Inquiry is "to identify lessons that can be learned". The central lesson – that toppling the leader of a sovereign country without a mandate from the UN might have unpredicted and highly damaging consequences – seems to have escaped Tony Blair even now.