The Americans made a mistake when they handed their fate over to the UN

One question is now obsessing official Washington. When does a prevarication become a casus belli? The Americans know that Saddam has been trying to acquire weapons of mass destruction. They do not have anything like a complete picture of his capabilities, but they know more than enough to prove there is a lie at the heart of the thousands of pages with which Saddam is trying to deceive Hans Blix, the United Nations and world opinion. So does British intelligence.

The Americans also now know that there have been links between Saddam and al-Qa'ida. Here, the CIA was slow on the uptake. The assumption had been that a secular Baathist regime could never do business with Islamic fundamentalists, and the CIA stuck to that for some time after 11 September. It is now clear that the intelligence agency was underestimating its adversaries' ruthlessness, and their willingness to collaborate on the basis that my enemy's enemy is my friend. But the CIA has caught up with events. The Bush administration is fully aware that its Middle Eastern foes are linked in an axis of evil.

So what happens next? Both sides have their eyes firmly fixed on late February. Each is aware that this is the last convenient date for an invasion. Thereafter, the heat of the day would make life intolerable for invading troops having to wear heavy clothing designed to protect them from chemical or biological weaponry, and from dirty bombs.

That is why Saddam has produced these thousands of rambling pages. He is now relying on Hans Blix's inveterate legalism and addiction to due process. A thorough scrutiny of the minutiae of deceit would inevitably take months: well past February. Hence Saddam's delaying tactics, reinforced by the "apology" to Kuwait. It is all a masterpiece of cynicism, but cynicism sometimes works.

There are certainly grounds for cynicism about arms inspection; the whole concept was flawed from the outset. Under the terms of the 1991 ceasefire, Saddam was obliged to destroy all his weapons of mass destruction, without assistance from the inspectors. The inspectors' role should have been a later one; to monitor a stable state of disarmament. They were never equipped to play hide-and-seek with Saddam in a country the size of France. Hans Blix himself was as little suited to have dealings with Saddam as Lord Halifax was to get the measure of Hitler.

But it will be difficult for America to override Mr Blix. Once the administration agreed to take the UN route, it tacitly accepted UN timescales. It remains to be seen whether a means can be found to force the pace. It may be that the Americans will decide to produce conclusive evidence of Saddam's deceptions, even if this means compromising vital intelligence sources. After all, those sources would lose their importance once Saddam was overthrown.

That overthrow is now the basis of American policy in the Middle East, a policy which alarms some Europeans because of the intensity of its idealism. As one senior official put it, the US is not like old Europe: it cannot go to war out of realpolitik.

America fought the First World War on the basis of Woodrow Wilson's 14 points; in the second one it was FDR's Atlantic Charter. Then came the Cold War, which was not won solely with the threat of Star Wars, but by Andrei Sakharov, Vaclav Havel and the Helsinki declaration of human rights. Even in Vietnam, America did not only fight to prevent the dominoes of South-east Asia collapsing into communism; it fought from a naive conviction that a democratic model could be exported to a far-off country with no democratic tradition and in the grip of a civil war.

This brings us to another fundamental difference between European and American assumptions. As another senior American put it: "You Europeans are racialists. You may talk about Arab rights, but you don't really believe that Arabs are fit to govern themselves. We do."

Reinforced by victory in the Cold War and the transformation of Eastern Europe, this belief in the healing power of democracy is basic to American thinking, as is optimism about the possibilities of progress in human events. The Americans do not see why there should only be two choices in the Middle East: psychotic predators or vulnerable autocracies.

Sentimentally attached to some of those vulnerable autocracies, Europeans are much more cautious. Contemplating the possibilities of chaos "makes us rather bear the ills we have/Than fly to others that we know not of". Nor do we believe that a latter-day Woodrow Wilson charging around the Middle East handing out rights to small nations would necessarily be a good idea: "Who wants a Kurdistan?"

As for democracy, it would be useful in Iraq and Iran, but it is much less clear whether it could be helpful in Algeria, Egypt or Saudi Arabia – any more than it was in Germany during the 1930s or would have been in Iran 25 years ago.

The Americans believe that vox populi is always vox dei. Europeans fear that in the Middle East, they could be right, in that the outcome might be a succession of terror-sponsoring theocracies. (There is, of course, one point on which the Americans and the Europeans change sides. Europeans wish that the Americans would show more enthusiasm for Woodrow Wilsonism and democracy when it comes to the Palestinians.)

These theoretical debates will continue, but the practical realities are more urgent. The Americans are determined to insist on a new dispensation in the Middle East. In this regard, there was a significant personnel change last week, with Elliott Abrams becoming the White House's director for Middle Eastern affairs.

Mr Abrams is a controversial figure. During Ronald Reagan's administration, he had a serious falling out with the Senate, after he concealed details of the administration's Central American policy in order to prevent that policy from being sabotaged by premature publicity. In response, the senators displayed a traditional American aversion to realpolitik, and demanded that Mr Abrams be indicted. Fortunately, he was pardoned by George Bush Snr.

It was assumed that this would be the end of his career in public service, but his considerable abilities have earned his recall. There would be no point, however, in making Mr Abrams director of a policy unless it were intended that there should be a dynamic, forward policy; otherwise, Elliott Abrams would merely waste his talents in frustration. Yet he will not be able to achieve anything as long as Saddam remains in power. Unless there is an invasion before February, Saddam will have more time to acquire terrible weaponry and to discredit America.

Walter Raleigh once sent Elizabeth I a note urging a certain course of action. "Tarry not, madam," he wrote, "for the wings of time are tipped with the feathers of death." The Bush administration now needs to remember Raleigh's message. It is time for rapid and decisive action.