IS THERE anything we can do about the atrocities committed by the Bosnian Serbs? Of course there is. We could saturate the former Yugoslavia with troops; we could bomb the Bosnian Serb strongholds and supply lines; we could even bomb Belgrade. But, as the Americans learned in Vietnam, the consequences of this kind of military involvement are unpredictable. It cannot be sustained because public opinion in democratic societies will not stomach the harsh, sometimes inhumane, actions needed to prosecute such wars. Democracies are squeamish about war; this was why Western governments pursued appeasement in the Thirties and this was why the policy was so popular. Television coverage has made democracies all the more squeamish. People like reading military adventure stories; they like war memoirs and war games and war films. But they do not like seeing women and children hurt and they do not want "our boys" to be put in danger. (One of the curiosities of the modern era is that young men still join armies, entirely voluntarily, but do not expect - or, at least, their mothers, wives and girlfriends do not expect - that they should run any greater risk than a travel courier). Wars need to satisfy several conditions if they are to command support. They must be invisible, in the sense that television has limited access to the battlefield; they must not involve babies, and particularly not white ones; they must be short; and they must seem to involve some national interest, if only a "kith and kin" sentiment. The Falklands and Gulf wars met these conditions. The war in Yugoslavia cannot.

For these reasons, the only sensible way in which the West can help the Bosnian Muslims is by arming them. This may lead, in Douglas Hurd's phrase, to a level killing-field; but it is hard to see why this would be worse than an unlevel killing-field in which "our" side occupies the lower ground. But it should be understood that the level field may prolong the war and that the Muslims are "our" side partly because they have had the worst of the fighting so far.

Last Friday's Lancaster House conference will lead nowhere. We have been here before, many times. "The current Bosnian Serb offensive and the siege of Sarajevo," said Malcolm Rifkind, the Foreign Secretary, after the conference, "defy international law and opinion." This echoes what John Major said at the close of another conference in London in 1992: "The participants ... condemn the continuing violence in Yugoslavia and reject as inhuman and illegal the expulsion of civilian communities from their homes to alter the ethnic character of any area." We are now assured that a mailed fist lies behind the expressions of worthy concern and that the Serbs will be sent a serious ultimatum. Perhaps they will; perhaps there will be a little bombing; perhaps more troops will be committed. But the results can easily be predicted. The Serbs will consolidate their gains and lie low; Mr Milosevic in Belgrade will make soothing noises; UN convoys will be harassed a little less than recently. Then, in a few months, the Serbs will advance again, overrunning more Muslim-held areas, taking and killing more Muslim prisoners, while Western and UN leaders order the mineral water for yet another conference.

The best the West can now do in former Yugoslavia is to allow this ghastly war to enter an even more ghastly end-game. It has been approaching that point for the past three years, but in slow motion because of the western involvement. Ultimatums have been issued; the Serbs have ignored them. Lines have been drawn; the Serbs have crossed them. Rapid reaction forces have been promised; they have been very unrapid. The whole performance recalls Lear in his madness: "I shall do such things - /What they are I know not - but they shall be /The terrors of the earth."

But Lear was a tragedy - and this has been a tragedy for the inhabitants of the safe areas who stayed in them because they thought they would be protected; for the UN which now has about 80 per cent of its soldiers in Bosnia protecting other UN soldiers; for all those in the war zones, who have had less humanitarian relief than if the charities had been left to it; and for the Western democracies who thought they could bring peace but have abjectly failed to do so. Only pride and machismo now hold the politicians back from withdrawal. And only a reluctance to admit that wars involve taking sides prevents them from arming the Muslims.