THERE are many good arguments against war, but high among them is its ability to bring surprises, many of them unpleasant. The second Iraq war was no exception to that, though it may have been unusual in bringing surprises both to those who were in favour of it and to those against.

Many advocates of the war were surprised by how rapidly it was won, by how few casualties were caused among both soldiers and civilians, by the fact that no biological or chemical weapons were used by Saddam Hussein and, most controversially, by the fact that no stockpiles of such weapons have yet been found in Iraq. Advocates were also surprised and dismayed, though, to find that America appeared to have no coherent plan for what to do in Iraq once the war was won. Many of those who were against the war were also taken by surprise, however, by its speed, by the lack of a deadly street battle for Baghdad, of a flood of refugees or an epidemic of cholera, and by the lack of uprisings or instability in other Arab countries and of terrorist attacks during the war. Most were further surprised, though presumably not dismayed, by the serious commitment to Arab-Israeli peace shown by President George Bush soon after the invasion.

More of those surprises have been pleasant than unpleasant, though it is too soon to make a definitive reckoning of that sort. In Iraq, many civilians feel insecure and poorly served with such basics as electricity and clean water, and American soldiers are being killed almost daily. The ceasefire in Palestine is fragile and the talk of peace negotiations and roadmaps always at risk of collapse. Nevertheless, three months after the war was won, one question demands to be answered, mainly because no weapons of mass destruction have yet been found: was the war really justified?

People who favoured war on the ground that Saddam Hussein posed a threat by virtue of his weapons must, if they are honest, admit to feeling undermined and even slightly unnerved by the fact that none have yet been found. They could well still be found: Iraq is a big country, chemical and biological weapons are often small, and Mr Hussein was shown during the 1990s to be a past master at concealment. Three months is not long for a search, especially amid the chaos and other tasks of the immediate post-war period. Still, the fact that no stocks have been found does at least imply that weapons were not widely deployed for use during the war, as otherwise some would surely have been captured during the allies' rapid advance. The British government's much-derided claim that weapons were capable of being launched within 45 minutes therefore does look to have been wrong.

However, the question of whether the war was, in retrospect, justified does not rest on that claim, or on the issue of whether Mr Bush or Tony Blair may at times have gone too far in turning possibilities raised by their spies into apparent certainties. Rather, the justification for the war is best addressed by dividing it into three questions: 1) Were there good grounds to threaten Mr Hussein with an imminent military attack if he did not comply with United Nations resolutions? 2) When he did not comply, were there good grounds for carrying out that threat? 3) After the military victory, have the allies acted in such a way as to make things better both in Iraq and in the region as a whole?

Mr Hussein himself provided the answer to the first question. He had signed an agreement in 1991, after the first Iraq war, under which he promised to get rid of his nuclear, chemical and biological weapons and programmes, to scrap long-range ballistic missiles, and to stop brutalising his people, among other things, all within a year. He did not comply, and UN weapons inspectors established that he had concealed his weapons, thanks to tip-offs from defectors. For example, having at first denied that he had ever produced a deadly nerve agent called VX, he then responded to a discovery by claiming to have made only 200 litres, but then the UN inspectors showed that at least 3,900 litres had been made. Having established that he could not be trusted, inspectors were barred from Iraq after withdrawing in 1998. Given that, by 2002, he had flouted 16 binding UN resolutions, how best to persuade him to allow inspectors to return? By making a credible threat that the measure promised by such resolutions, the use of force, would be carried out if he didn't. That required the stationing of troops on his border and the passing of a further UN resolution in November stating what he had to do to comply.

None of that has been called into doubt by the lack of discoveries since the war. Mr Hussein had a clear record of developing these weapons, using them and concealing them. There can also be no doubt both that he was a brutal, ruthless dictator who murdered hundreds of thousands of his own citizens and that he harboured ambitions to dominate his region: he had fought Iran during the 1980s, had invaded Kuwait in 1990, and threatened Israel, Saudi Arabia and (in 1994) Kuwait again. He was thus plainly a dangerous man, in whose hands such dangerous weapons could pose a real threat, both to regional peace and, through the power that dominance of the world's oil reserves would bring, to the whole world.

Reasonable people could disagree about that decision, and about whether it might have been better first to get a unanimous vote on a new Security Council resolution. But neither the non-discovery of weapons nor the recent evidence of exaggeration by the British and American governments of elements of their claims alters the argument for or against permitting further delay. Mr Hussein was believed, on good grounds, to be both dangerous and a liar. On previous occasions the UN process had fallen apart after delays led to divisions. The attempt to use containment, sanctions and inspections had lasted 12 years: hardly a sign of impatience. The prospect that he could emerge from it able, after a year or two, say, to revamp his weapons programmes and threaten his region was real. Both at the time, and in retrospect, the decision to go to war rather than to wait was justified.

What then, it is reasonable to ask, might change The Economist's mind? If Messrs Bush and Blair are shown not just to have exaggerated but actually to have lied, knowingly putting false information before their voters, it would be a huge scandal and would destroy their governments' credibility for future interventions overseas. But to make the Iraq war look unjustified in retrospect, such a scandal would have to amount to clear evidence that it had not, in fact, been reasonable to believe that Mr Hussein was a dangerous liar and concealer—which would require the distortions or deceits to have been astonishingly widespread and conducted over a long period of time. Given that spying agencies currently look incompetent rather than capable of such a broad, effective campaign, this looks unlikely. But there is another mind-changing possibility. It lies in the answer to the third question: After the military victory, have the allies acted in such a way as to make things better both in Iraq and in the region as a whole? If they hadn't, or didn't in the future, that could indeed make us decide that the war had not, after all, been justified.

It is, of course, far too soon to come to a judgment about this. What can be said, though, is that so far the picture is mixed but on balance moderately encouraging. President Bush has certainly begun a serious effort to persuade Israel and Palestine to make peace, and that process has inched edgily forwards. The future question will be whether he maintains that effort in the face of inevitable setbacks, and of the fact that both Yasser Arafat, still the Palestinian figurehead, and Ariel Sharon, the Israeli prime minister, are reluctant either to compromise or to help build trust. There is also the distraction of the 2004 presidential election in America. The grounds for cautious optimism are that President Bush really cannot afford to shrink back now that he has made his commitment; and that the opportunity for change provided by the victory in Iraq will not last forever. That must be the hope, and must be what Mr Bush's allies should urge.

In Iraq itself the Americans made an appallingly bad start. Their reasons for having had no post-war plan are almost as incomprehensible as Saddam's reasons for having neither complied with the UN resolution nor deployed any banned weapons. They have also failed, so far, to beat back or deter the guerrilla tactics being used against them. There are, though, some encouraging signs too. Chief among them is the establishment during the past week of the new 25-member Iraqi Governing Council, the first big step the Americans have taken towards devolving power to Iraqis themselves and towards establishing some sort of representative democracy.

The new council (see article) is far from democratic—its members were picked by Paul Bremer, America's chief administrator, albeit after consultation—but it is fairly representative. It is hardly surprising that it took three months before such a council was set up, given that Iraq has only just emerged from a long and repressive dictatorship. But the delay still sowed doubts about America's intentions. So too has the slowness, in the face of sabotage, to restore electricity supplies. America's predicament is that it must simultaneously prove that it is committed to staying in order to rebuild Iraq as a secure, stable and peaceful country, and that it is preparing to hand over power to democratic institutions and to leave.

Making the council a success will be an important part of that. So too will be the commencement of real work to prepare for elections, first at a local level and later at national level. Alongside that, however, there can be no substitute for the deployment of people and money: more troops, to pacify the areas of Iraq in which guerrilla campaigns are being fostered and to show that America is not going to allow the Baathists to claw their way back; more money, to restore utilities faster and as a further show of commitment, particularly given that oil exports have been much slower to resume than was expected.

But will America really remain committed, especially in the face of daily casualties? Again, the answer is that it cannot afford not to be. Afghanistan has been left, both by America and by other rich countries, in far too vulnerable and disorderly a state. That is tragic and shameful, but if the same were to happen in Iraq the result could be catastrophic: a deadly civil war in which neighbouring countries felt they had no option but to become involved, and a huge stain on America's reputation, not only for justice but also for effectiveness.

In America's history there are too many examples of a short attention span. But there are also bigger examples of the country's ability to pick itself up after initial stumbles and to sustain a long-term commitment: the troops that have sat in danger by North Korea's border with the South for 50 years; the Marshall Plan that boosted Europe's economic recovery a full two years after victory in the second world war. Again, a long-term, costly commitment is going to be needed.