Several simple lessons stand out about how to conduct constructive negotiations to resolve international conflicts peacefully. Unfortunately, the diplomatic process that preceded the current aerial bombardments ignored or violated most of those principles, which might well have prevented the present conflict.

First, timing is important. There generally are two periods in the evolution of a conflict when conditions are likely to be ripe for negotiations. The first comes in early stages of the conflict, when the issues have become clearly delineated but have not yet produced a violent reaction. Once violence has begun, emotions become intense, stereotypes form, desires for revenge overwhelm rationality, and parties dig in their heels and refuse to compromise, even if a settlement would be beneficial.

The second opportunity usually comes only after a long period of conflict, when both parties are exhausted, when there is a stalemate, when both parties are suffering the pain of conflict, and neither perceives that it stands to gain from its continuation.

That was the situation that led to the Dayton accords in 1995 which ended the fighting in Bosnia.

Unfortunately, the first "window of opportunity" for negotiations over Kosovo closed early in 1998, when the conflict escalated into violent clashes between increasingly militant Kosovar Albanians and the Serbian police and army.

Before March 1998, there had been numerous warnings that the conflict would soon turn violent. Yet no political commitment was forthcoming from the United States or its European allies to initiate high-level negotiations. By the time talks opened in Rambouillet, France, earlier this year, it was too late.

It may now take months or even years before the parties reach a painful stalemate when the negotiating window may reopen. In the interim, thousands are likely to die and hundreds of thousands will be displaced from their homes.

Secondly, while third parties can play a useful role in negotiations, mediators must avoid the temptation to impose their own solutions. Instead, they need to listen patiently to the grievances, needs and interests of the disputing parties and guide them to solutions that the parties recognize are in their own interest. Otherwise, they will have no incentive to implement what they sign.

This was the tragic mistake of the agreement brokered by U.S. envoy Richard Holbrooke between Kosovo Albanians and Serbs in October 1998. The ink was barely dry before both parties began violating this agreement.

The unarmed monitors sent into Kosovo under the auspices of the Organization for Security and Cooperation in Europe did their best to assure implementation of the agreement, and they resolved numerous disputes before the situation exploded. But in the end, they were no match for the extremists in both the Kosovo Liberation Army and the Yugoslav government in Belgrade who had little incentive to uphold the agreement.

And again at Rambouillet, the United States and the other members of the "contact group" tried to impose a settlement on the parties. It should hardly have come as a surprise that the Kosovo Albanians signed only reluctantly and under threat of dire consequences, whereas the Yugoslav government refused to sign at all.

Finally, it's important to remember that sovereign states do not often yield to coercive threats. If anything, such threats and coercion produce greater unity and determination. Successful agreements are more likely to be achieved when powerful third parties offer a judicious mixture of sticks and carrots.

Yet in the Rambouillet negotiations the United States and its allies made only threats of military action against Serbia and threats of abandonment before the Serb onslaught against the Kosovo Albanians. We failed to show the parties how their acceptance of peace could lead to a significant improvement in their peoples' lives.

At no time between 1991 and 1997, when this conflict slowly escalated toward violence, were there offers of significant economic aid to assist the parties out of their increasingly desperate living conditions, which had themselves become a major incubator of conflict. Desperation and the lack of attractive alternatives to their plight more than any primordial ethnic hatred has led to the current fighting in Yugoslavia.

The U.S. Congress especially has usually opposed economic aid on budgetary grounds, even though no one seems to question the vast sums of money spent in the air war. Had the money that has been spent in just one day on bombs and missiles been invested in economic development programs in the Balkan region just five years ago, it is unlikely this war would have occurred in the first place.

What makes the whole situation so tragic is that a little judicious foresight, combined with these few well-known principles of diplomacy, could have prevented this tragedy. Somehow we keep repeating the same mistakes, at great cost in terms of wasted resources and the loss of human life.

When will we ever learn?