WHEN THE HISTORY OF NATO'S DEMISE is written, the entire affair, it will be said, was rich with irony. It was on the eve of the Washington Summit in April 1999. Western leaders were preparing to toast each other in the American capital when a defining moment inconveniently emerged, courtesy of Slobodan Milosevic.

NATO had won the Cold War -- decisively and without firing a single shot. The alliance had just extended its zone of freedom and stability into the heart of central Europe. And NATO was positioning itself to meet the challenges ahead. Its concerns would range far beyond simply defending itself. The new NATO would have a say about proliferation, terrorism, rogue states, and regional threats. After all, even the "indispensable nation," as secretary of state Albright liked to call the world's only superpower, needed its allies. And the Atlantic community, with all its power, remained, as Albright said the year before, the "drive wheel of progress on every world-scale issue." Heady stuff. And spirits were high, until a 57-year-old Balkan banker and ex-Communist bureaucrat pulled the curtain down on what was being celebrated as the most successful alliance in history.

Of course, NATO is not dead, not yet anyway, even though the administration's start in Kosovo has been dangerously inauspicious. But the Western alliance may yet a die an ignominious death if President Clinton doesn't set aside his golf clubs and finally grasp what is at stake.

For a decade now, Milosevic has terrorized NATO's backyard, threatening to spread war and destabilize neighbors. Even as the West temporized over the Bosnia in the early 1990s, Ibrahim Rugova, a leader of the Kosovar Albanians, was telling the world that ethnic cleansing in Kosovo was "still Milosevic's ultimate objective." And now, as the West dithers once more, Milosevic is on the March again. At this stage, only a decisive American-led victory and an unambiguous Serbian defeat will give peace an opportunity in the region -- and permit the alliance a future after this month's 50th anniversary summit.

We've come up with several excuses for our inability to deal with Milosevic. Conflict in the Balkans, some said, was an insoluble clash over religion and ancient hatreds. The bloodshed was, others contended, "not within NATO's defense zone." Reaching still further, President Clinton infamously proclaimed, "the United Nations controls what happens in Bosnia."

Best of all, perhaps, we liked blaming the allies. The Europeans -- led by the Germans -- prematurely extended diplomatic recognition to the breakaway republics Croatia and Slovenia, making war in Bosnia inevitable. The Europeans rejected arming the Bosnians for self-defense. They frequently used the authority of the U.N. Security Council as an excuse for inaction and remained obsessed with diplomacy, even though it failed and meant appeasing a dangerous tyrant in their midst.

Has anyone noticed how the tables have turned? Even a left-learning popular German magazine seems to have gotten the idea. "If [NATO] succeeds," writes editor in chief Michael Maier of Stern, "the Americans will be more than the world's policeman: As moral authority, they'll be able to promote and defend the Western value system worldwide." The allies have finally stepped up and the alliance faces an extraordinary moment. Europe seems to be grasping more quickly than Washington the implications of allied disunity and capitulation. The Belgian daily De Standard accepts the idea of ground troops precisely because the West's failure against Milosevic "would be worse than a defeat"; it would be "an unacceptable loss of credibility" for NATO and for the United States. A victory for Milosevic would, contends Milan's Corriere della Sera, "diminish [NATO's] ability to avert other wars, whether in the Balkans or elsewhere."

A dozen of NATO's 18 members are already participating actively in Operation Allied Force -- with France, of all countries, joining the United States in the lead. The German newspaper Frankfurter Allgemeine Zeitung beat American hawks to the punch in calling for air strikes deeper into Serbia, so that "the dictator [Milosevic] fears for his own life." Even Germany's Social Democratic chancellor Gerhard Schroder has held the line, enduring criticism from leaders of his party, while his Green foreign minister Joschka Fischer owned up early to the fact that only ground troops would likely get the job done. Germans, usually reluctant to intervene, have even been worried about premature peace.

Across the Rhine, leading French intellectuals applaud the alliance for finally saying "enough" to Belgrade. Foreign minister Hubert Vedrine defends NATO's action and points out that "this tragedy in Kosovo has been smoldering for 10 years . . . [and] everything that has been attempted has failed." Dismissing suggestions from the French press that Paris is "playing the Americans' game," Vedrine Calmly insists that it's the wrong time to argue "in terms of competition between Europe and the United States." French philosopher Pascal Bruckner argues, "In the face of horror . . . we must reaffirm that we share the same values as America." Bruckner also warns that anti-American forces are already well positioned to take advantage of an American-led fiasco.

And what of American leadership so far? President Clinton rules out ground troops. Defense secretary William Cohen states that air strikes will inflict "enough damage to reduce [Milosevic's] capacity to wage war against the people he's been killing." And when bombing makes the humanitarian nightmare worse (and Milosevic predictably shows no signs of surrender), a senior U.S. officer involved in planning the campaign actually tells the Washington Post, "We didn't plan for the worst-case scenario."

Of course, we can complain that the Greeks waffled; that the Italians worried about the impact the war would have on tourism; or that the allies initially resisted targets in Serbia for fear of collateral damage. In the case of Milosevic's presidential palace, we might even complain that West Europeans dragged their feet because the site is a "cultural landmark."

But the fact is, we may look back soon and recognize that there was a time in this war, at a pivotal moment in alliance history, when Europe was with us. Right now is that time. Europeans aren't bent on negotiating with a war criminal; Europeans seem to recognize that additional force is necessary. Meanwhile, we are becoming known as the superpower that doesn't do ground troops. NATO could come to an end now, not because of weak-kneed Europeans, but because of the failure of its leader, the United States of America.

Jeffrey Gedmin is a resident scholar at the American Enterprise Institute and executive director of the New Atlantic Initiative.