One of the great H E Bateman's cartoons shows "The Criminal Who Admitted Everything". To the consternation of the judge, barristers and clerks assembled in court ready to earn their keep in a full-dress trial, the fellow standing in the dock throws up his hands with a cheeky grin and says it was a fair cop.
In moments of idle fancy, one dreams that Tony Blair's appearance at the Chilcot inquiry next Friday might be like that. "Yes, of course I took the country into a needless and illegal war. I knew very well that the intelligence about Saddam Hussein's weaponry was limited, but George Bush was going to invade anyway and I wanted to be there, even if my Cabinet and the Labour MPs and the British people didn't. That was why I had to exaggerate the WMD claims so grossly."
Dream on. What we are going to get on Friday is another display of sinuous evasion and denial, with the committee trying but mostly failing to land a few blows on Blair as he ducks and dives. His successor is another matter. Poor Gordon Brown quite lacks Blair's glib self-assurance, and the appearance Brown has now agreed to make some time before the election is bound to see him writhing like a wounded animal.
And yet, the Chilcot inquiry has already been very damaging for Blair. Combined with so much we have learned elsewhere, it has contributed to the accelerating collapse of his position over Iraq. On Thursday's Today programme, Hans Blix, the former weapons inspector who had found no evidence of WMD in Iraq before the invasion, courteously said he didn't think Blair had acted in conscious bad faith. Can even that be sustained any more?
It's very well for remaining Blair loyalists to damn the throng of witnesses before Chilcot who "suddenly discover a conscience and that all along they were worried about the prime minister's strategy", as Denis MacShane, the former Europe minister, wrote in these pages on Wednesday. He almost has a point, and the testimony of the former ambassadors and mandarins has been odiously self-serving.
There is nothing very dignified about the way they have been covering their backs and settling the score, with some of Blair's erstwhile cabinet ministers now doing the same. With all his "profoundly difficult moral and political dilemma", Jack Straw almost admitted to Chilcot that the war was a mistake, and suggested that he would have preferred to keep out of it.
But then there's a score to settle. What MacShane fails to acknowledge is that Blair bullied and browbeat Cabinet, Parliament and the whole civil and military elite into a war almost none of them really wanted – and that what he has said since, not least in his gruesome television interview with Fern Britton before Christmas, has horrified his former colleagues, or well nigh betrayed them.
He really is a very strange creature, with his exalted sense of destiny, his total lack of scruple when he thinks the ends are justified, his readiness to use fair means or foul to get his way, and in particular his quite remarkable capacity for selective amnesia. One consequence is that he often fails to see that he is completely contradicting himself, and in the process humiliating his faithful allies.
To borrow a hallowed phrase from Irish politics, those who trusted Blair have again and again been left with their arses hanging out of the window. He did that with Roy Jenkins over electoral reform, with Paddy Ashdown over an alliance between Labour and Lib Dems, with David Trimble over IRA violence, and with his credulous pro-European supporters over the European constitution.
In the summer of 2004, Blair performed an excruciating about-turn, announcing a referendum after he had cut a deal with Rupert Murdoch before the election. Then, in the spring of 2005, he duly won, just as the constitution was rejected by the French electorate. On 5 June Blair told the Commons that, after the French vote, "there is no point in having a referendum", at which Angela Browning, the Tory backbencher, reminded him that he had told The Sun less than four weeks earlier, "Even if the French voted no, we would have a referendum. That is a government promise".
And he has done it over Iraq, in a manner so flagrant as to raise doubts about his mental stability, or at least suggest that he has no grasp at all of objective truth and falsehood. In the Commons on 13 October 2004, he denounced the Liberal Democrats, saying that if they had their way, "Saddam Hussein and his sons would still be running Iraq. And that is why I took the stand I did. I take it now and I at least will stick by it". At that, the Labour MP Bob Wareing asked him how he could explain having told Parliament on 25 February 2003, "Even now, today, we are offering Saddam the prospect of voluntarily disarming through the United Nations. I detest his regime but even now he could save it by complying with the United Nations' demands".
Then in that interview before Christmas, Blair talked about how his Christian faith sustained him, before he was asked whether "If you had known then that there were no WMD", he would still have supported the invasion, and replied: "I would still have thought it right to remove him. I mean obviously you would have had to use and deploy different arguments."
It simply didn't occur to him that those words must produce howls of agony and rage from those who had served in his government seven years ago. Like Straw, they all thought that regime change as such was an "improper and unlawful" reason for war, but Blair effectively concedes that this was really the purpose, just as some said all along. Washington was going to invade in any case, and so-called WMD were, as Paul Wolfowitz memorably put it, a "bureaucratic" or cosmetic pretext.
But if Blair had "deployed different arguments", he wouldn't have been able to take his country to war at all, as he knows very well. Come to think of it, maybe he really is the criminal who admits everything.