The meeting in Washington has been an extraordinary Nato summit, part celebration and part council of war.

It has inevitably been overshadowed by the crisis in Kosovo, but that has not deflected the Alliance from looking ahead to its future roles and missions.

For in a sense, Kosovo is Nato's future. How the Alliance deals with this crisis in the Balkans, and perhaps more importantly its aftermath, will determine the way in which it is perceived during the early years of the coming century.

Jonathan Marcus: Nato's big test

That is why Nato is so confident about its eventual success in the campaign against Yugoslav President Slobodan Milosevic. If the Alliance cannot achieve its aims in Kosovo then its future role as a regional security organisation will have been stillborn.

Already in Bosnia and now in the air over Yugoslavia, Nato has shown that it is unique in being the only multi-national defence organisation that can mount military operations of this scale and complexity. But this is, in a sense, a test of the old Nato.

The Alliance's military professionalism and competence has never been in doubt. What is much more debatable is its diplomatic sure-footedness.

Political weaknesses

Many commentators have criticised the way it stumbled into this conflict. Nato's military strengths have been exemplified in this war, but its political weaknesses are also apparent.

This is a war waged by a 19-nation committee, whose members sometimes seem uncertain as to whether they really are at war at all.

Nato's ambitious future agenda will require the development of diplomatic skills to match its military capabilities. Here, too, Kosovo will be a test.

Whatever the outcome, Nato ground troops are likely to be stabilising the region for some time to come, and this raises fundamental questions about Nato's future expansion, and its developing network of partnership programmes with countries beyond its own frontiers.

Here, too, the Balkan crisis has focused minds and changed the terms of the debate. No new members will be joining Nato for the immediate future.

But Nato's relationship with countries like Albania, Macedonia, Romania, and Bulgaria will be critical in helping the Alliance to stabilise south-eastern Europe.

This summit has proposed new consultative mechanisms for the region, which will run hand-in-hand with the stability pact proposed by the European Union.

Of course, security for the Balkans as a whole is the central issue, but Nato knows that only through economic assistance and the eventual opening up and liberalisation of markets, can long-term security be achieved.

In this sense, security in the widest terms goes way beyond Nato to include institutions like the EU, international financial bodies and a network of bilateral and multi-lateral ties between individual organisations.

Bringing south-eastern Europe into the continental mainstream is Nato's declared aim, but it is a task that Nato cannot perform alone.

Determination and unity

Many people thought that this Washington summit would be a time for wavering and that the first cracks would appear in Nato's united front to prosecute this war to its conclusion.

But the message from Washington has been one of determination and unity.

Nato knows that discussion of a ground intervention in Kosovo is divisive and might stretch the current consensus to breaking point.

Nonetheless, Nato commanders are weighing up the options and more Nato troops will gradually flow into the region, in the first instance to prepare for peace-keeping duties.

But as Nato's air campaign is stepped up, which is another product of this summit, the military balance on the ground will shift in Nato's favour.

Some form of ground operation may become both militarily and also politically feasible.

Relations with Russia

This summit has also served to limit the damage to Nato-Russian relations. These are clearly strained.

But Russia's diplomatic efforts have been received politely, and even the much-discussed Nato embargo on petroleum products is unlikely to strain ties further, except at a rhetorical level.

Russian oil has so far only gone to Serbia via the Danube, and this route has been blocked by Nato air strikes.

The summit has focussed heavily on the post-war settlement in the Balkans even as the air campaign continues. So far Nato has managed this crisis well.

It emerges from this summit intact, determined and even optimistic about its future. Nonetheless, the challenges ahead are formidable.