A couple of weeks ago, the Canadian television presenter Richard Gizbert asked a panel at the Frontline Club in London what effect WikiLeaks' disclosure of American cables might have had during the run-up to the Iraq war. Would the kind of revelations we saw last year have made it impossible for Tony Blair and George Bush to invade Iraq on the basis of claims about weapons of mass destruction?

Obviously, publication would have made deceit and obfuscation vastly more difficult, because the more the public is made aware of what governments know and don't know, the more difficult it is for politicians to follow messianic crusades of their own. That is one of the crucial arguments in favour of publishing such material. Contrast the clear shafts of light that spread from publication of the cables with the interminable ramblings of John Chilcot's committee of pensionable British worthies and you find yourself regretting that the manoeuvrings of Blair and Bush were not exposed to similar scrutiny in 2002 and 2003. Is it any wonder that the internet generation largely supports the dumping of raw information by whistleblowers on the web when they see figures from the 20th-century British establishment like Chilcot forlornly apply to make public two letters from Blair to Bush, only to be refused on the grounds that prime ministers and presidents have a right to keep their correspondence private?

The request was passed by the cabinet secretary Gus O'Donnell to Tony Blair, who naturally declined to give his consent, the same reaction no doubt as Richard Nixon would have given if he had been asked, rather than forced, to allow the Watergate tapes to be played in public. But the moral possession of these letters does not lie with Blair, the state or even the historians of the future, but to the British people of today – the public who paid for his Iraq adventure in money and lives. The confidences between statesmen are as nothing compared with the public's right to know what went on in the lead-up to war.

When Blair won the battle of the letters, he was halfway home and that was before he even set foot in the inquiry last week. Plenty was revealed, but he never looked discomfited during his appearance and any admission of failure only served the self-portrait of an agonised leader who was merely trying to do right by his country. He has an impressive armoury of tricks designed to draw sympathy from his audience or at least to stall his interrogators – the dramatic hesitation as he recalls those difficult months, the empty concessions to the views of opponents, the frequent use of "in respect of", "look" and "I have to say", all of which serve to evoke a reasonableness which is wholly bogus.

When he was being ever-so-gently pressed on the question of why the attorney general Lord Goldsmith was not involved in discussions in the months between October 2002 and January 2003, he came out with a contorted explanation about keeping the Americans in ignorance of the doubt of his cabinet and the government's chief legal officer. "I had to hold that line – very uncomfortably by the way," he said with a familiar dash of self pity. It is clear there was never any question in his mind that he wanted to take the country to war; what he in fact admitted in this exchange was the subtlety – some would say cunning – with which he manipulated the public and political discourses towards that end. When asked why he had ignored Goldsmith's unambiguous advice that UN resolution 1441 was not enough to go to war in a speech to the House of Commons, he made the truly baffling distinction between a political and a legal speech, as though the first somehow gave him licence to say anything he wanted, whereas a legally informed statement would be more constrained.

I have no proof, but suspect that Blair was not conscious of the difference at the time. He can be remarkably hazy about the law and once stated in these pages that the Human Rights Act does allow the courts to strike down the act of our "sovereign parliament", which it most certainly does not.

His passing admissions underline this intellectual laxity, though you would not know it from the reaction of the five members of the inquiry. As an aside, Blair revealed that only 14 of 28 meetings with key figures to discuss the possibility of war were actually minuted; no record exists of who was there or what was said at half of these meetings.

Chilcot's purpose is to write a report, not create a courtroom drama for television. The questioning is respectful, sometimes over-elaborate but rarely forensic, which is a pity because on these issues the public does need to see political leaders visibly held to account, even if that means impolitely forcing them to answer difficult questions. According to a US diplomatic cable published by WikiLeaks in December, the British government promised to protect American interests during the inquiry, which may account for the suppression of the Bush correspondence. One cannot help feeling that the entire process is far too gentlemanly and that Blair will now return unscathed to his life as a quasi-financial, quasi-political, quasi-religious entrepreneur, not unlike the character described in Robert Harris's novel The Ghost.

A report will eventually be extruded by the Chilcot committee, by which time most people will have long since given up caring about Iraq. It will no doubt make sensible mandarin points about the law, proper procedures and good government, but as with the other inquiries into Iraq, the British public has been deprived of proper satisfaction. We don't need a show trial, just a sense that penitence of a genuine sort or an admission of guilt has been wrung out of some of the Chilcot's witnesses, especially Tony Blair.

But maybe this is not our way. There are already important lessons to be learned about our recent history and the dictatorial way Blair ran the government at the height of his power – how easily checks on him were bypassed, opposition thwarted, intelligence skewed, lawyers and obstructive colleagues sidelined, all in the mortifying attempt to earn the favour of the US and pursue a policy of "liberal intervention" that was, by the way, in part developed by Chilcot committee member Sir Lawrence Freedman.

The thing is that we don't have to wait for the report to understand what happened; it has been plain for the last six or seven years. But imagine how things would be if we had known then what we know now. Real-time disclosure makes deception very hard.