The images and stench of death drift from the villages of Kosovo, and it is hard to suppress the urge to punish a nation for its inhumanity. In an orgy of cruelty the Serbs have wiped the memory of their own suffering and heroic resistance to Nazism and become the pariahs of modern Europe.

In the face of such atrocities, what does it matter that NATO's behaviour fell short of angelic? Dresden never stopped us keeping the horror of the concentration camps in focus and seeing the Allied cause as justified in that moral framework. Those who wanted peace with Hitler are consigned to the cesspit which history reserves for "appeasers". The purple prose of victory seems a small price to pay for the illusion of moral clarity. The cry "Never again!" is once more vindicated in the stories of what the Serbs did and what NATO's victory appears to have stopped.

But the facts matter. The lessons of this war will not feed into Western consciousness in the way most decent people imagine. There will not be another military campaign against brutal dictators, and those who remain within Europe's reach can rest assured that the Serbs will bear the brunt of the conscience of the world for many years. The memory of Kosovo will feed into the militarisation of European security and be used to continue its dependence on American intervention through NATO.

Leaving aside the problems of legality, consistency, even-handedness, more serious questions of fact are central to any conclusion of ethical import. The now-indisputable fact that the Belgrade military deserved to be annihilated and that Milosevic is a war criminal is irrelevant to the ethical assessment of NATO's resort to war.

This jars with our instincts of compassion and righteousness, but it must be stressed in relation to Kosovo as it must also in regard to the Nazi concentration camps. What matters is what NATO knew on March 23rd when, we were told, all alternatives to war were exhausted.

Likewise, the fact that NATO's victory brought the termination of ethnic cleansing is not the point. Had NATO lost it would not thereby have forfeited a moral judgment on the justice of its war. We may thank God for NATO, as the Jews did for the Allies, without allowing that emotion to colour our moral judgment of the victors and their wars.

What was known about Serb atrocities and plans before the war began, and did it justify war as a response? I doubt if we will ever know the definitive answer. The evidence (of official US sources, among others) does not support the view that in three months before the war there was a level of systematic killing comparable to what later ensued or a Belgrade plan to implement it. They may be wrong, but we need a high degree of certitude that other options to achieve NATO's humanitarian aims were exhausted before we can justify taking the horrific step of war.

Were there other options? Western commentators repeat the claim that there was no alternative with a confidence which is astonishing in the light of the clear and publicly-available evidence to the contrary.

The NATO aims, setting out the moral justification of war if rejected by the Serbs, were well publicised in the famous five principles. Essentially they required an end to violence, withdrawal of Serb forces, the return of refugees, and "an international military presence" in Kosovo.

Throughout the war the Western media linked this humanitarian concern with images of cleansing and death, nudging our moral sensibilities to contrast NATO's humanity with Serb bestiality. But NATO wanted more than we were told.

The Rambouillet Agreement presented to the Serbs in February and March was not published, though it was available in full to all major news agencies, all of which appear to have extracted only the summary information which made sense in the light of NATO's declared aims. The document's demands included the relief of the Kosovars, but also the acceptance of NATO presence in the whole of Yugoslavia; an absurd proposition if the securing of humanitarian aims without resort to war was its intent.

Every attempt to negotiate after that was a failure, not just because of the desperation of Milosevic to save face, but also because of the relentless efforts by NATO to exclude the UN as the controlling agent of the peace-making force, and to margina lise Russia.

Even the near-failure of the military arrangements in the tent in Macedonia in June was later revealed, in mainstream US media, to have been caused not by Serb trickery, as generally announced at the time, but by NATO's attempt to excise the role of the UN in the administration of the agreement.

In the end, what was agreed in the UN Resolution of June 9th was substantially in line with the ending of violence, the return of the refugees, and the stationing of an international peacekeeping force in Kosovo, all of which the Serb National Assembly had offered on March 23rd, but which went unreported in our media.

The Serbs are ultimately responsible for the brutality. But NATO bears responsibility for adding its institutional supremacy to the bottom-line conditions for peace and resorting to war when a UN-centred proposal accepting the substance of their declared aims was finally on the table.

Dr Bill McSweeney is head of the international peace studies programme at the Irish School of Ecumenics and editor of Moral Issues in International Affairs, Macmillan UK