Leading article: Despicable means to a dead end

What are we to make of Tony Blair's admission that he would have joined the invasion of Iraq even without evidence that Saddam had weapons of mass destruction, and would, as he put it, have deployed another argument to justify the war to Parliament and the public?

He has, of course, inched before towards a confession that the war was really all about regime change, stupid. Never mind that this would have made it even less defensible on legal grounds. It was all long ago, and, as he says on BBC1 today, the world's a better place without that evil man with the bushy moustache and his two nasty boys.

Even by the standards of the former prime minister's chutzpah, this I'd-have-deployed-a-different-argument approach is extraordinary. What is worse than requiring us to view very differently the presentation of the "extensive, detailed and authoritative" WMD evidence – surely the most cynical con trick of modern times – is Mr Blair's sly reference to Islam, in which he moves on to another justification, fixing the decision to go to war in the context of a wider battle over religion: "I happen to think that there is a major struggle going on all over the world, really, which is about Islam and what is happening within Islam."

This is as fine an example of Mr Blair's intellectual dishonesty as it is possible to find. As a statement, it is, of course, uncontroversial. Applying it to Iraq, though, is scandalous. There is an arguable case, and one which Blair now seems publicly to endorse, that Saddam simply had to go. In which case, why did he tell the Commons in February 2003 that it was not too late for him? "I detest his regime. But even now he can save it by complying with the UN's demand." Sir John Chilcot might care to ask Mr Blair if that, like so many things he says, merely felt true at the time he said it.

And why did he speak, in the parliamentary debate on the eve of invasion three weeks later, of rogue regimes and terror groups? It was to invite the gullible to make the inference he wanted – that Saddam's regime was somehow implicated in 9/11.

Mr Blair's comments to Fern Britton in today's programme are designed to convey that same false idea. You might – might – argue that military action in both Afghanistan and Iraq is part of the same war, to stop WMD at some distant time falling into the hands of terrorists. But that overlooks Saddam's bitter hostility to Osama bin Laden, of which Blair must have been aware, and the creation of al-Qa'ida in Iraq since the invasion.

Of course, to argue that Saddam was such a threat that invasion was the only solution, Mr Blair needed a reason, particularly to convince the public that Saddam was a threat in 2003 when he had not been in 1988, after the Marsh Arabs genocide, or in 1991, after the first Gulf War, or in any of the dozen months of the dozen years before war began.

So that is where the WMD evidence came in. It is now clear from what Mr Blair says that this was simply a means to an end, simply cover for the fact that he (or, rather, George Bush) had decided that he wanted Saddam out. As Mr Blair says: "I mean, obviously you would have to use and deploy different arguments about the nature of the threat." Talk about a God complex.

What are the implications of this for the Chilcot inquiry? It has been a rather odd affair already. A very British farce, if you like. Mandarin after mandarin has – metaphorically, and as only our civil service can – tiptoed backwards from the room as the war is discussed, effectively to say, "Old boy, we knew it was all dubious at the time, but," – shrug – "what can you do?"

As Alex Carlile points out on page 41, we will be denied the cathartic satisfaction of seeing the chief culprits skewered by an eagle-eyed lawyer. This is a pity. The state of Iraq and the death toll, of at least 100,000 over the past six years, demands that those responsible should be held to account. Of course, we will have to suspend judgement until the final report, but the signs are not encouraging.

The great shame about Mr Blair is that he was right about liberal intervention. We were right to do what we did in Kosovo, and, had he been around in 1992, we can be pretty sure that the Bosnia catastrophe would not have been allowed to happen. But his early successes coloured his judgement, and led him to disaster. What is surprising about today's interview is the lengths of intellectual contortion to which he will go to avoid ever having to acknowledge it.