If the party leader had ever run a ministry, would he be in this mess?

In the end all that matters is the bleakly obvious. Britain went to war because of the imminent threat posed by Saddam. We know now that Saddam posed no immediate threat. It is debatable whether he posed any threat at all.

This is why the question of trust hovers darkly over Tony Blair. Our boys were sent to Iraq over weapons that did not exist. The rest of the media din is largely irrelevant. Was Geoff Hoon in Poland on the day that The Sun published its front page about the September dossier? If so, could he have still read the newspaper and sought to correct its over-excited reaction to that document? These are questions that have been raging around Westminster, but I doubt if Hoon's presence in Poland was of much interest to the Poles, let alone to the British electorate.

Similarly Michael Howard's call last week for Tony Blair to resign has failed to make much impact. Implicitly Howard called for the Prime Minister to step down three weeks ago by suggesting that he had lied to the Commons over the naming of Dr David Kelly. Calling for a prime ministerial resignation is thought to be the Leader of the Opposition's nuclear option. Howard has pressed the button twice and nothing much has happened. Perhaps that is partly because the Conservatives supported the war and made no complaints about the September dossier at the time it was published, even though their leader had been shown the intelligence on which it was based. The Liberal Democrats are on stronger ground and have made an astute decision to keep clear of the inquiry on the intelligence that was set up last week.

Some ministers are suffering from inquiry fatigue. Yet another bloody inquiry, they moan, as if there is nothing new to discover. But the previous three inquiries were more about the media than the war. The Hutton report investigated some overblown journalism, foolishly defended. The reports by the two parliamentary committees became almost wholly diverted into proving also that the journalism and its defence were sloppy. There has not been a serious inquiry into why the intelligence was badly wrong or whether Tony Blair misinterpreted the material available to him.

The increasingly anxious ministers protest that they wish to return to the domestic agenda, to focus on schools and hospitals (but not transport, I suspect). Their protests are both pointless and without justification. They cannot and should not achieve closure on the war while it appears that Britain took part in a conflict on a false premise. In particular Blair's current statements on the quality of the intelligence and the decisions he took in the build up to war are contradictory. He continues to insist that British intelligence is the finest in the world, proclaiming regularly that we should all be proud of it. If that is the case then Blair is to blame for misrepresenting their fine work on the nature of the threat posed by Saddam. But the Prime Minister does not accept blame. He insists his judgement was based on the assessment presented to him by the intelligence agencies. Blair cannot have it both ways. Either the intelligence was at fault, or he is to blame for making too much of the material provided by the agencies.

Forget about the absurd row over whether Downing Street, or Hoon in Poland, should have corrected the few newspapers that ran dramatic headlines about Iraq's 45-minute threat. The affectations of outrage ignore entirely the context in which the dossier was published. In the days leading up to the publication there was much fevered speculation that the document would be a damp squib. After publication there was a fair amount of comment that the dossier was indeed full of information that was already widely known. Within a few days the media was focusing with good cause on John Major's relationship with Edwina Currie, an affair started, consummated and over within what seemed like 45 minutes. The newspapers had forgotten about the dossier. Before Currie's revelation the dossier became briefly part of the debate raging about Iraq. The pro-war newspapers reported the dossier as confirming Iraq's imminent threat. Those that opposed the war played down the significance of the document. Blair and Hoon were hardly likely to admonish the pro-war newspapers. They needed all the help they could get. They were not running an adult education class, but a nervy campaign to convince MPs and the voters of the need for war.

How did they get in such a position in the first place, publishing speculative intelligence to justify an unpopular war? This is a question that is more central than Hoon's reading material in Warsaw. It takes us to a deadly irony. I suspect that Blair went to war partly because "Old Labour" had not been trusted to defend Britain. From the beginning of his leadership he resolved to show that New Labour would be different, that it could be trusted to form a military alliance with the US even under a Republican President. Blair's restless desire to purge Labour of its past has led to a predictably dark twist. Now he finds himself less trusted than some of his Old Labour predecessors, unable to move on from a war that ended nearly a year ago. This is what is so politically dangerous for Blair and his Government. He can no longer dictate the political agenda.

Indeed, it is more serious than that. Old Labour was not trusted on defence in the sense that voters concluded that they could not rely on it to defend the country. Blair is not trusted because some voters and large parts of the media have ceased to believe him.

The reality is more complex. The Prime Minister got into this mess because he sought the support of the UN and needed the backing of a majority of his own MPs. He became far too dependent on the intelligence to make his case. Probably he believed most of the intelligence, partly because he desperately needed it to be right and also because of his own inexperience. As Blair joked last week, he has an "unusual CV" in that he has never been a minister. He soared straight to the top. Such a rise must have been simultaneously gratifying and terrifying, explaining quite a few of New Labour's neurotic errors. I suspect if Blair had been a foreign secretary in the past, observing a prime minister wrestle with erratic intelligence, he would have acted differently in the build-up to war.

But he did not. He went to war over weapons that do not exist. A combination of factors got the better of him: Prime Ministerial inexperience, those 18 years in opposition, and a curious mixture of self-belief on the one hand and electoral insecurity on the other. This issue will not go away. Schools and hospitals must wait.