That, according to Tony Blair, is the essence of Nato's war aims: that these people should go back to their homes. But what exactly would this require? What is the minimum we must insist upon?
The minimum is an international protectorate for the whole of Kosovo, to which the majority of those who have been expelled will both wish and feel safe to return. With each week that passes, the difficulty of achieving this increases.
The auspices for this protectorate should ideally be those of the United Nations. Whether Russia and China - after having its embassy bombed - would now agree to that is very doubtful. To achieve the elementary security without which the expellees would not return, a large international force would be needed. This is what British troops are training for in Macedonia. Even with a negotiated agreement, it would - initially at least - probably require more than the 28,000 soldiers envisaged in the Rambouillet agreement. If Serbia proper had not been militarily defeated, and Milosevic not replaced by someone more reasonable, then our troops would have to secure Kosovo's external security against a revanchist Serbia as well as its internal security against any remaining Serb soldiers, police, paramilitaries and armed civilians.
Again and again I asked the expellees in the camps what it would need for them to return. Their answer could be summed up in a single phrase: "no Serbs with guns". But if the Serbs are disarmed, what about the KLA, to whose colours young Kosovars in exile are now flocking? The KLA would surely flood back as the Serbs retreated, firing their Kalashnikovs in the air, as they did after the cease-fire agreement last October. And they would terrorise any Serbs remaining. If the place is to be half-way peaceful, the international force would need to make a stab at disarming them. But decommissioning a guerrilla army is a very difficult task, as we have seen in Northern Ireland.
Then, who would maintain law and order? A whole new police force would have to be created from scratch. Someone would have to train it. Nato soldiers say that is not a job they are either equipped or ready to do. Meanwhile, many people have no homes to go back to, and no crops or cattle to see them through the winter. So a massive effort would be needed, first by the UNHCR, to put roofs over their heads and to feed them, then by governments and charities, probably co-ordinated by the EU, to reconstruct the infrastructure destroyed by Serb forces and by Nato bombs. "Kosovo is lost for me," one exiled newspaper editor told me. "The place is just destroyed; it will take 20 years to rebuild it." Even if the Serbs are defeated, we shall still face the enemy called despair.
To vanquish despair, the Kosovars will need their own political leadership. We talk all the time about the international framework. In the acronymic jungle of planning for peace, the OSCE is assigned the role now curiously called "nation-building": supervising elections, building up democratic institutions and so on. But what about the people whose homeland this is supposed to be? One voice that has been missing over the past two months is that of Kosovo. We have heard the refugees and, as Hillary Clinton mawkishly put it, "felt their pain". But the Kosovars have featured only as victims - as objects rather than subjects of history.
The trouble is that their political leadership is hopelessly divided. There is the pacifist President, Ibrahim Rugova, widely discredited by appearing on Serb television with Milosevic while his people were being rounded up and killed. There's a "prime minister in exile", who controls the money collected from Kosovo Albanians living in the West. There are KLA commanders besieged in mountain pockets across Kosovo, and KLA leaders squabbling in Albania. And there are the liberal intellectuals of Pristina, now to be found in the Cafe Arbi in Tetovo, Macedonia. They are desperately looking for their Havel, Gandhi or Mandela.
In one respect, and one only, Kosovo should be easier than Bosnia. In Bosnia, the international community is trying to maintain the semblance of a multi-ethnic state, but the reality on the ground remains one of ethnic partition. In Kosovo, we must certainly strive to see that there is a place for innocent Serb civilians in a territory that holds so much Serb history. We must not ourselves become party to a revenge "ethnic cleansing", as we were in the Croatian Krajina. But I fear that, in practice, even the most innocent Serbs are likely to flee. Even if they stay, and are given all possible minority rights, the combination of demography and democracy would mean that this would still be essentially an Albanian political entity. As a result, a viable Kosovar polity could grow up under international tutelage - in a way that is, alas, most unlikely ever to happen in Bosnia.
The Russians will have to be part of this international framework. They are an essential part of the solution. They are also part of the problem. The Kosovars don't trust them at all. "They are worse than the Serbs," one Albanian patriarch told me. "They are all Slavs," his son explained. If Russian soldiers stand at the frontier, refugees will be reluctant to go back. But there is a worse variant, which Milosevic will almost certainly try for. This is a Russian zone of occupation in the north and east of Kosovo, where the mineral wealth and some of the main Serb monasteries are. What this would mean in reality - as it did in Germany after 1945 - is partition. Serbs would go to the Russian part; Albanians to the rest.
One has to be very clear about this: such a "face-saving compromise" would be a defeat for Nato. For several years now, even Serb nationalists have been talking about partition as the only solution for Kosovo. It would also encourage Albanians to say: all right, if you, the West, are ready to accept the partition of Bosnia and Kosovo on ethnic lines, we will divide Macedonia on ethnic lines. It would be a disaster - and Milosevic could plausibly claim victory.
The trouble with this war is that it is being fought in the wrong place. A war in Kosovo for Kosovo seems to me wholly defensible. A war fought - because of the American paranoia about taking casualties - from the air over Serbia proper, against increasingly civilian targets, is much more difficult to defend without reservation. While no one really knows what is happening inside Kosovo (except perhaps the Serb military), the bombardment has not prevented more than a million people - according to US State Department estimates - being driven from their homes there. Equally, no one really knows what is happening inside the Milosevic regime, but we do know that the bombing has devastated the small democratic opposition in Serbia.
What we should aim for is exactly the other way round: a situation in which, in Serbia proper, Milosevic loses rather than gains popular support, while we at last do something effectual in Kosovo itself. The distinction between fighting for Kosovo and fighting against Serbia may seem a fine one - too fine for wartime - but it remains vitally important. Rather than bombing Serbian towns, we should be liberating Kosovan ones.
If the minimum political objectives I have outlined above could be achieved by negotiation, I would be as happy as anyone. But I don't think they can be achieved without at least a credible threat of ground troops. So, two months into the war, our stark choice may be: accept defeat, or prepare ground troops.
The author's new book, `History of the Present: Essays, Sketches and Despatches from Europe in the 1990s', is published by Penguin on 14 JuneReuse content