Alastair Campbell's inquisitors may have fallen into a trap of their own making

The committee has allowed itself to be hijacked by the issue of whether Campbell inserted the '45-minute' threat into the first dossier

No more Mr Nice Guy. Now that the full-scale row between the Government and the BBC has turned ugly, it's time to ask what we have learned about the man who brought it to a head. Alastair Campbell's performance on Wednesday was certainly box office, and his follow-up last night even more aggressive. The sock it to 'em, give as good you get, seize the moment decision to turn the issue into a battle with the BBC that Downing Street appears to think it can win are all part, it seems, of why he was apparently clapped as he returned on Wednesday evening to the press office in Number 12 Downing Street - the building he symbolically requisitioned from the government whips after the last election.

Secondly, you got a glimpse - almost for the first time in public - of his centrality as an enforcer not only to the Blair operation but to the whole government machine. This is a man who is able to talk from a position of equality - or something more - with the most senior permanent secretaries, security service chiefs and cabinet ministers. A man whose calls round the Whitehall village are returned pretty damned quick. A man who speaks casually of John Scarlett, the chairman of the Joint Intelligence Committee, as "a friend of mine".

It remains to be seen whether he will fulfil the widespread predictions, which he calls "wishful thinking", that he will be leaving soon. Certainly he has thought of it several times, not least in the run-up to the last election, and again when the Cheriegate affair exposed a real fissure between himself and his partner Fiona Millar on the one hand, and the Blairs on the other, about the intimate and unusual influence in the family's private counsels of Carole Caplin. As the devoted father of two sons he would certainly get his life back. Never mind the memoirs, which will guarantee, to put it at its mildest, a handsome pension. The idea that anyone as intelligent, efficient and determined as Campbell couldn't easily pick up - say - a plum job in television or in many other walks of life is risible.

On the other hand, those who still see him going the distance with Blair have a point. For he is politically acute, and not a man to leave his friends in the lurch. He is ultra-loyal to any cause he believes in, from Burnley FC to the Labour Party and its leader. Indeed, there is more than a hint of Leninism in his attitude to the need for all good men to come to the aid of the party. He has an addictive personality, channelled into work as it was once, by his own admission, channelled into alcohol. He may throw up his hands and say he's had enough. But like almost every other marathon runner, he has a masochistic streak that could just, in the end, see him through.

One argument frequently trotted out is that having too often become "the story", he should move on. But a weightier factor is the political vacuum he would leave around Tony Blair - greater, arguably, than if he had left in the first term, when true Blairite believers, Peter Mandelson included, were rather more numerous in the Government than they are now. That makes him important in two ways, not only as the Prime Minister's political bodyguard, but also as one of few - by now probably very few- people in Tony Blair's inner circle who can say no to him, largely to the Prime Minister's own benefit.

Which brings us back to Wednesday's hearing. It was, by all accounts, Campbell's own decision to go before the committee, against a prevailing "office view" in Number 10. And it comes with a price. It enabled the committee to confirm that Campbell had at least a hand in the drafting of the first, September dossier. More important, it will help to throw even more of a spotlight on the Foreign Affairs Select Committee at the expense of the rather more decorous and experienced Security Intelligence Committee, on which Number 10 had previously been counting to draw the line under the affair of the dossiers. (It will still be interesting to see whether the latter committee will touch on an earlier unease among some in the intelligence services, virtually ignored by the Foreign Affairs Select Committee and arguably vindicated by events: not so much about whether their advice was "sexed up" but whether it ought to have been made public at all.)

But it may well be a price worth paying. Alastair Campbell hasn't - couldn't - wipe away the damage caused by the "dodgy" dossier. As a tactic, the ferocity and personal nature of his onslaught on the BBC and the Today programme's defence correspondent, Andrew Gilligan, is questionable. The refusal of the PM to take a BBC question at the Putin press conference is even more so. Wider complaints about the BBC's coverage of pre-war dissent have a McCarthyite ring to them, threatening to obscure the Government's more specific case. But Campbell will still be seen in government as having helped to put it on the front foot in its increasingly unedifying fight with the BBC - the fiercest since Norman Tebbit's attack on Kate Adie's reporting of the bombing of Tripoli.

It is all very well saying this is a diversionary tactic. It has nothing to do with whether the Government placed excessive faith in unvarnished intelligence judgements that Saddam had weapons of mass destruction. Still less does it go to the heart of the fascinating and - politically, morally and historically - far-reaching question at the heart of the enquiry's official title: "The decision to go to war". But that's entirely the committee's fault for allowing itself to be hijacked by the single issue of whether Campbell did or did not (as he asserts with increasing confidence) insert the now-famous "45-minute" threat into the first dossier.

For the deficiencies of the enquiry go beyond a lack of forensic skill, an inability to react to individual answers, a tendency for individuals to grandstand, and a even a failure to open, as barristers often do, with a few apparently "soft" questions which often produce revealing answers: "Just why did you want to put the concealment briefing into the public domain in February - was it to discredit the UN inspectors?" Some of this anyway could be improved by much better staffing on the lines of US Congressional Committees.

No, it stems much more from the obsession with process that infects almost every aspect of modern politics. An obsession that obscured some of the vastly more important issues at the heart of the decision to go to war in Iraq. It's incredible that when Jack Straw, Britain's Foreign Secretary, appeared - for a much shorter time, of course, than the Downing Street director of communications - he was asked nothing about his own part in anything but the dossiers. Why did he say at one point that the prospects were 60-40 against war? Why did he change his mind? Why - a point raised by Robin Cook here yesterday - were some of the threats in the dossier not repeated in the Commons in the crucial, much later debates?

These are just a few of the questions that have hardly troubled the committee. And if process is all you care about, then it's more difficult to complain if the master-processer threatens to take the trick.

d.macintyre@independent.co.uk