SADDAM HUSSEIN's mind runs on fairly predictable tracks. When he sees an opportunity for gain he seizes it. When he senses weakness he exploits it. When he wants to know the mind of his adversary he tests it. Sometimes he miscalculates, as when he invaded Kuwait. More often he draws back just before a confrontation, as he did when he placed missiles north of the permitted line in the spring of last year.

Now he has approached the brink again by moving anti-aircraft missiles into the no-fly zone in the south, where they seem likely to be bombed by the Gulf war allies if they are not withdrawn. Perhaps he sensed an opportunity because of the changeover in Washington and hoped to cock a final snook at President George Bush, whom he regards as a very personal adversary. If so, he has miscalculated and may yet realise this in time to withdraw before the allied deadline expires tonight. Or he may be planning to sacrifice a few old-fashioned missiles in order to stiffen the backbones of his supporters and find out what sort of forces the allies are capable of putting into the air.

Whatever the answer, the allies have no choice but to insist that the missiles be withdrawn, and to bomb them if they are not. If the allies' will or military capacity is being tested they need to demonstrate that neither has weakened. Any compromise or delay would be quickly exploited by President Saddam to throw off the restraints he finds so irksome and to continue rebuilding his power.

Militarily, the tasks should be simple. Politically, there is still a firm enough consensus in place for maintaining pressure on President Saddam. There would even be a case for simultaneously knocking out the artillery that is being used against the Shias in the southern marshes, since the legal justification for military action would be UN Resolution 688 of 5 April 1991, which condemned 'the repression of the Iraqi civilian population in many parts of Iraq . . . the consequences of which threaten international peace and security in the region'.

Admittedly, that resolution makes specific reference only to the Kurdish-populated areas, and was drafted with them in mind. For this reason the Secretary-General of the United Nations is reported to be unhappy about using the resolution as a general cover for allied military intervention in Iraq. There is, in fact, no specific UN approval for the no- fly zone, and there are doubts among some members about letting the burgeoning doctrine of intervention on behalf of human rights develop too swiftly.

In this case, however, there is very broad agreement that President Saddam remains a potential threat to the region and that, if he cannot be removed, he must at least be forced to comply with the restraints imposed on him after his defeat. Nor can there be much disagreement with the proposition that his treatment of his own people is an example of the way in which gross violations of human rights within a country can threaten international peace, as Resolution 688 asserts. If further legitimation of military action is required, it can be found in Resolution 678 of 29 November 1990, which authorised the use of force to reverse the invasion of Kuwait and to restore international peace and security in the area. President Saddam still frustrates the completion of that task.