Never again. That is the plea behind every exhibit on the Holocaust, every teacher's assignment of Eli Wiesel's Night, every classroom showing of Steven Spielberg's Schindler's List. The hope, sometimes even the claim, is that once we know and see how one group of people has consciously and purposely destroyed another group of people, then we will be inspired to resist the temptation to stand by if it happens again.

And then it happens again. It has happened in Cambodia, in Bosnia, in Rwanda, in Kosovo. What has become of that "Never again"? Is it merely a phrase we utter to console ourselves, a wan hope (at odds with the Christian understanding of human sin) that the race must after all learn something from its horrific past?

The genocide against the Albanians in Kosovo has at least forced us to ask what we mean by "Never again." More precisely, we are forced to ask what price we are willing to pay, if any, to back up that "Never again." Perhaps what we really mean is "Never again--unless we're asked to take some risk." Or: "Never again--unless the outcome of our efforts is in some way in doubt." Or: "Never again--unless it means sending ground troops."

The U.S. and NATO cannot avert every massacre. Realistically, if China were to start a wholesale slaughter of Tibetans, the West could do little about it, for practical and political reasons. But because we cannot act against every case of genocide does not mean we should never act.

NATO's goal in Kosovo has become clear: to allow the refugees from Kosovo to return to their homes so that Slobodan Milosevic's ethnic cleansing is not allowed to stand. To ensure the refugees' safe return, an international military force--preferably with Russia involved--will be needed to occupy the province. Kosovo will probably need to be made a protectorate, under the auspices of the United Nations, providing full citizenship to Serbs and Albanians and protection of the Serbs' holy sites. A UN protectorate is hardly an ideal solution. But it is far better than the alternatives.

The military experts say it will take six weeks to get ground troops ready to enter the region. NATO should start assembling these troops. That show of resolve will give Milosevic further reason to accept a diplomatic resolution. We hope that the troops will become a peacekeeping force, not an invasion force. In any case, we do not expect peace and a modicum of justice in Kosovo without a price.