Not through its military efforts or in the political arena - but the alliance's response to the aid crisis has been outstanding
Something unique happened on Thursday afternoon, at the refugee camp called Brazda, close to the border of Kosovo and Macedonia. It began after lunch with the sound of distant chanting on the far side of the huge tent village. The cameramen and reporters hurried in its direction, and round a corner emerged a remarkable procession.

It was a large crowd of children, several hundred in all, and growing all the time, shouting, marching and waving placards. The oldest were young teenagers, the youngest were toddlers, hoisted on the shoulders of their elder siblings. The placards were in carefully printed English, the chanted slogans in Albanian, and they were dominated by one word.

It was hard to make out at first, because in Balkan languages, it is pronounced with a short "a", to rhyme with "gateau". "Natto! Natto!" shouted the marchers. "Thank you, Natto!"

The demonstration was not organised by the children, of course - a small group of frowning adult refugees discreetly marshalled the youthful crowd, encouraging the tinier among them to hold their placards aloft so that the photographers could get a better shot. But the sentiment was certainly genuine. "Thank you Nato," read one of the more unwieldy placards, "for the friendship that you have shown Kosovar refugees."

Had there ever in history, before the war in the Balkans began last month, been a pro-Nato demonstration? Throughout the Cold War years, as the military bulwark against the forces of the Warsaw Pact, the North Atlantic Treaty Organisation brought a feeling of anxious security to the countries of the West, but hardly the kind of high emotion which brings crowds of kiddies out in praise.

In capital cities from Belgrade to London, the noisiest demonstrators have been those excoriating Nato - for the muddled planning and rather fruitless execution of its bombing raids, culminating last Wednesday in the deaths of dozens of fleeing refugees mistakenly bombed by an American F-16.

But here in the camps, for the first two weeks of this crisis, Nato has been everything - the provider of food, water and shelter, the guarantor of peace and security. Nato representatives watching the marching kiddies in Brazda appeared perplexed, almost embarrassed, by the scene. "We're, er, delighted of course that they have found what we've done of value, especially the children" said Tim Cross, the stalwart British brigadier responsible for logistics at the camp. "Whenever we are asked, we will help."

Military presence in the camps was being scaled down throughout last week, as Nato formally handed over their administration to the United Nations High Commissioner for Refugees (UNHCR). By this weekend, the intention was that the 12,583 Nato troops would return to training and preparing for their original task as the Nato Peace Implementation Force - the peacekeepers who, theoretically at least, will one day enter a Kosovo free of Serbian soldiers to enforce Nato's terms.

But with tens of thousands more refugees expected to make the crossing into Macedonia in the next few days, the chances are good that Nato will soon be back building camps, and helping refugees - the only job, so far, in which it has acquitted itself with honour fully intact.

Apart from being a much-needed public relations coup, at a time of confusion and embarrassment within the organisation, Nato's transformation into humanitarian saviour has implications for all of the international aid- giving community.

Tracing responsibility for the refugee crisis which has swamped Macedonia and its neighbour, Albania, in the last three weeks is a tricky undertaking, but it is certain that Slobodan Milosevic's ethnic cleansing of Kosovar Albanians would have proceeded at a far slower pace if Nato had not launched its air strikes. But having triggered the problem, and completely failed to anticipate its scale and speed, Nato did more to alleviate it than any of the organisations which formally exist to deal with refugees.

Nato's response eclipsed that of the UNHCR, whose reputation as the world's social security agency remains tarnished by its handling of the first weeks of the crisis. As tens of thousands of Kosovars wallowed in mud for three days at the Macedonian border earlier this month, the High Commissioner for Refugees, Sadako Ogata, wrote to the Nato secretary-general, Javier Solana, to admit that her organisation had been "overwhelmed". The next day, Nato created a Refugee Support Co-ordination Centre at its Belgian headquarters in Mons.

As of last Friday, Nato had flown in 4,083 tonnes of aid to Macedonia alone, including 1,100 tonnes of tents. Notionally, this was provided under the supervision of the UNHCR. But between the elegant Mrs Ogata and the hulking figure of the Nato commander in Macedonia, Lieut-General Mike Jackson, there is little doubt who commands more authority.

As a military command designed to wage war, Nato has obvious advantages over the sprawling bureaucracy of the UNHCR and its auxiliary agencies. When supplies were being flown into Macedonia, many of those arriving on commercial aircraft were held up by customs. UNHCR officials had to bite their lips and wait; Nato officers were able to avoid the red tape altogether by ordering military transports to bring the aid direct.

Officially, the organisation portrays itself as a willing, but temporary, Good Samaritan with no intention of adopting a permanent humanitarian role. Politically, as well, the issue is sensitive: earlier this month, Russia complained in the United Nations that the UNHCR was coming under Nato control.

Apart from its humanitarian efforts, the conduct and progress of the war has so far convinced almost no one. In the Macedonian capital of Skopje, pro-Serb activists have been handing out leaflets in which a few extra strokes have converted Nato's distinctive star into a Nazi swastika. It will be hard for Nato soldiers to walk away from the relief and gratitude in the camps, into the hostile, sceptical world outside.