Like all successful wars, it will influence military thinking for generations. For the first time the case has been made that air power - not nuclear bombs, but conventional air power - has won a war on its own. And while the Gulf war was the low-casualty conflict, Kosovo has introduced the seductive concept of war without casualties at all.
In fact, the first assertion is not watertight. Appearances to the contrary, Kosovo is less than perfect proof that air power alone can win a war. In the end, it was the notion of ground war, first as a creeping local reality, then as a distant but terrible threat, that made Slobodan Milosevic blink. In the last couple of weeks, the Kosovo Liberation Army was making inroads from its bases inside Albania, enough to force the Yugoslav army to leave cover and engage it - at last making the Yugoslav forces easy targets for allied planes, operating in the clear skies of early summer. For all its protestations to the contrary, by the end Nato was serving very much as the KLA's air force.
Simultaneously, President Bill Clinton, having previously ruled out an opposed entry into Kosovo, let it be known in Washington that "every option was on the table", as Pentagon planners mused aloud about how to get 200,000 allied troops into the area to invade by August. For the Yugoslav President, the possibility of holding out until winter, and a negotiated settlement with his war-weary opponents, had vanished. And there is one other important difference from normal wars. Nato's campaign was not intended to defeat the Serbs in their own country, merely to force them to stop mistreating a province of whose population Serbs constituted less than 10 per cent before the crisis began. Finally, Mr Milosevic calculated that holy but overwhelmingly Albanian Kosovo simply wasn't worth turning into another Masada.
Like all wars, this war was one of a kind, whose recipe will not work in every circumstance. But many a general and Western politician will be itching to try it. Even more than the Gulf, Kosovo has been a showcase for warfare's third industrial revolution: first spears and bows and arrows; then the guns, superseded in their turn by mechanised armour, now overtaken by smart weapons, drones and the rest, as the command centre moved from the battlefield to the computer screen. With almost unbelievable results.
Yes, the war would have been shorter had the ground threat been brandished early on. Yes, some of the tragic mistakes which killed hundreds of Serb and ethnic Albanian civilians would probably have been avoided had the Nato pilots taken greater risks and flown at lower altitudes. As it was, in the course of 11 weeks, in which 900 aircraft flew 36,000 sorties and 12,000 bombing raids, the alliance lost just two aircraft and not a single life in combat - a tinier proportion than the average Western air force loses in routine training (two Apache helicopter crewmen died this way in Albania). Nato destroyed a quarter of Belgrade's tanks and planes and a third of its artillery pieces. By Mr Milosevic's admission, 462 Yugoslav soldiers died, although Nato puts the figure far higher.
The prospect is of more of the same. Kosovo has shown that America and its main allies have a technological advantage which can only increase. "The bombs and missiles will get even smarter and deadlier," says Anatole Lieven of the International Institute for Strategic Studies in London, "while the electronic wizardry that goes into them can be countered only by equal wizardry, beyond the reach of all but a very few countries - and, with the exception of Japan, none of them outside Nato." And herein may lie the real "Kosovo effect": not so much on the conduct of wars, but on the decision to go to war in the first place.
More than any recent war, Kosovo was conceived as an extension of diplomacy, another notch in the escalation of pressure against Slobodan Milosevic. Now that negotiation by cruise missile has been proved to work, Nato itself could come under pressure from human rights groups and others to so the same thing elsewhere to prevent manifest injustices; not only in its European backyard, but in the Middle East, Africa - or even, potentially most perilous of all, in Russia's backyard of the Caucasus and TransCaucasia. The next tinpot dictator who terrorises a neighbouring country or a section of his own people - why not give him the Milosevic treatment? No matter that bombing might not be much use to prevent another Rwandan genocide (in Kosovo the air strikes undoubtedly brought about an increase in the atrocities they were meant to prevent): the risks are non-existent and the cause is just.
Which leads back to what may be the most profound diplomatic legacy left by Kosovo, obvious even before the first missiles struck on 24 March. For all the lofty language about the first war in modern times fought not for national interest but for humanitarian motives (which Kosovo undoubtedly was), it was, and remains, equally true that Nato took international law into its own hands. Only at the end of the day was the United Nations brought into proceedings.
The alliance acted in the name of "the international community", though the only organisation which can lay claim to represent that nebulous entity is by definition the UN. Nato has moved closer to becoming the policeman of globalisation, with a self-granted mandate to impose Western values as and when it sees fit.
In the case of Kosovo, few would dispute that the values brutally trampled by Mr Milosevic were not so much Western but universal. But another time it may be less clear-cut.