We've seen the evidence. Now go back to the UN and set Iraq a new deadline

But I am more convinced that what marks Saddam Hussein out is his willingness to use weapons of mass destruction

We asked for a dossier on Iraq, we got a dossier on Iraq, and now we ditherers have to decide what to do about it. Starting with whether or not we believe it. Unlike the propaganda pamphlets of old, the dossier does make passing reference to the contrary case (as presented by the arms inspector Scott Ritter). Its language is restrained, and there don't seem to be any of those technological fantasies, complete with artists' impressions of impossible new airplanes, that used to characterise US intelligence briefings during the late Cold War. Even taken at face value, however, the dossier is not a revelation, but rather a reminder of things we should not have forgotten. It is not, in itself, a case for war. It is a case for action.

The two questions that the 50-odd pages seek to answer are these: since the withdrawal of the arms inspectors in 1998 and the consequent bombing of Iraqi facilities under the operation name of Desert Fox, has the Iraqi regime been trying to rebuild its capacity to make weapons of mass destruction (WMD)? And, secondly, would it be safe to assume that Saddam Hussein would not seek to use such weapons (or the threat of them) in an aggressive way?

There does seem to be limited evidence of a retained capacity for manufacturing chemical and biological weapons, and plenty of psychological reason for believing that the regime might now be adding to that capacity. On the nuclear front, the one genuinely shocking new piece of information concerns Iraqi attempts to acquire uranium in Africa, when there is no civilian application for it in Iraq.

But I am more convinced by the second case, the one that says that what marks Saddam out is his willingness to use these weapons, and that he believes that their possession (with the threat of their use) is an important part of guaranteeing Iraq's strategic position in the region. Developed during the Iran-Iraq war, at a time when the conflict was going against the Iraqis, chemical weapons and nerve agents killed 20,000 Iranian soldiers. Had the Iraqi nuclear programme not been delayed by – among other factors – the Israeli attack of 1981, and had the Iranians looked like winning that war, the chances of Iraq (which launched Scuds on Tehran) using a nuclear weapon would surely have been high.

The notion that Saddam is your usual run-of-the mill, wily (albeit nasty) politician does not survive a visit to the website of the Iraqi Presidency. There you will find that Saddam "led the Iraqi people wisely and bravely against the aggression launched against Iraq by Khomeini's regime on September 4, 1980, which ended in Iraq's great victory on August 8, 1988". And that he then "led his country in confrontation to the aggression launched by 33 countries led by US, which waged war against Iraq, known as the Battle of Battles, where Iraq stood fast...". You will also discover Saddam's frankly barmy speeches about geopolitics, speeches that make Mein Kampf look coherent.

On Monday, Panorama also featured a 1996 interview with Saddam's own Ribbentrop, Tariq Aziz, in which Aziz said that they biological and chemical weapons would never have been deployed in the 1991 Gulf War because one would not use them "against such an adversary". Against another adversary, one inferred, there would have been no such problem.

This was an unusual moment of candour. Until 1995 the Iraqis claimed that all talk of a biological weapon capacity was part of the imperialist-Zionist plot against them. In that year they finally admitted that, not only did they have 138 such weapons, but that 75 chemical or biological warheads were available for their ballistic missiles.

Since 1991 the Iraqis have complied belatedly, partially or not at all to a series of UN resolutions, beginning with resolution 687 of April 1991 and ending with Resolution 1284 of 1999. The authorities harassed the inspectors, hid material and undertook destruction of weapons themselves, rather than hand them over to the UN. There were incidents such as the claimed animal protein factory that turned out to be making anthrax and botulinum toxin.

There is (for God's sake) a pattern there. And those who believe that there is either no threat or a negligible one should begin to produce their own dossiers. In them they could seek to demonstrate how Saddam has now given up on the old WMD business and how he is changed and chastened and forever cowed. Scott Ritter himself accepts that Iraq could be substantially rearming by 2004, and even if it is right that 90 per cent of Iraq's WMD capacity was destroyed by 1997, that left 10 per cent on which to build in the last five years.

Which brings us back to Tony Blair's central claim that containment (ie a combination of sanctions and external monitoring) is not working. Sanctions are incompletely applied and regularly breached, and, in any case, they cause suffering for ordinary Iraqis while leaving their despots living in paranoid luxury. What he is saying is that the UN and the rest of us have let this drift since 1998, lacking a strategy to deal with the unique problem of Saddam.

I am with Al Gore in his attack on the astonishing way in which the hawks of the Bush administration, led by Dick Cheney, have squandered the goodwill of the post-11 September world. They have created the clear impression that they do not care whether the inspectors go back in, or even whether every dot and comma of every UN resolution is adhered to. Their objective is exemplary regime change, and that's that. And since, in the absence of a general insurrection, only war can achieve this, then war it must be. They cannot, they claim, understand our scruples.

And one awkward thing to be said for this position is that it alone seems to have forced Iraq to the point of readmitting the inspectors. But one senses that what some US figures want is proper war, and not just the threat. Just as there are others who oppose all forms of action against Iraq, including sanctions, believing, presumably, that all this stuff about aggressive dictators and poison gas is fairy-tale stuff to frighten the kids.

The rest of us, however (including the more reflective parts of the administration), have other options. It seems to me to be a perfectly proper response to the dossier to support a new UN resolution renewing and updating the tasks of the inspectors and setting a deadline for Iraqi compliance. If that should happen, then the issue of WMD should be pretty much settled, and we will not need to go to war.

This, of course, places the onus on Saddam himself. It's the kind of thing that happens to you if you habitually invade your neighbours, enslave your own people and use appalling weapons against both. Which is why a part of me hopes that he is barmy enough to prevaricate or to tell the UN to take a running jump, and that – if he does – the UN will have sufficient resolve to sweep him away. Then people will be killed but Iraq will be liberated. It's just that I'm not at all sure that it's a good part of me, if it wants war.

David.Aaronovitch@btinternet.com