in Washington - Back in the days of the Cold War, Hollywood producers of films like Amerika and Red Dawn imagined American life under foreign occupation. Turns out they had it all wrong. Last week, visitors to the nation's capital got a taste of the real thing. Barricades went up and government shut down. Federal workers went home. Museums locked their doors, forcing tour groups to wander aimlessly about the National Mall. Strange flags fluttered on downtown lampposts and on speeding black limousines with darkened windows. Helicopters crisscrossed the sky. Police officers in orange vests asked pedestrians for identification, while Secret Service agents and military personnel wandered down the middle of wide avenues closed to traffic. Bomb-sniffing dogs patrolled the sidewalks outside key federal buildings, and big blue vans from the Federal Emergency Management Agency waited curbside, in case the dogs missed something, perhaps. Welcome to America under foreign occupation-by her allies. The weekend ceremonies marking NATO's 50th anniversary attracted the largest-ever gathering of foreign leaders in Washington, D.C. The presidents or prime ministers of 42 countries flew in to celebrate, accompanied by some 1,600 foreign ministers, defense chiefs, and other top advisers. The partying was more subdued than originally planned. There was no parade down Constitution Avenue, and the scheduled F-16 fly-over was canceled. At all but one event, the dress code was downgraded from black tie to business attire. Toasting in tuxedos was considered bad form when thousands of Kosovar refugees were flooding neighboring countries wearing tattered rags. Indeed, the specter of the Kosovo crisis hung over the celebration like a pall. While protesters took to the sidewalks, the bigwigs argued behind closed doors. Britain and France urged ground troops, but Greece and Italy questioned the rationale for even an air war. The United States urged a naval blockade of the Balkans. France, Greece, and Italy all vetoed that idea. By all rights, the weekend should have been an uninterrupted party. NATO, after all, is widely regarded as the most successful military alliance in history. Without firing a shot, it won the Cold War, put an end to the arms race, created a dozen newly independent nations, and freed nearly that many more from Soviet domination. The first-time representation of Poland, Hungary, and the Czech Republic at the NATO summit offered proof that the West had won. As it turns out, winning has a downside. After you win, you're supposed to shake hands with the loser, walk off the field, and go home-something NATO has proven unwilling to do. Instead, it now finds itself mired in a war on Europe's extreme southeastern flank, far from the established democracies it was originally designed to protect. And despite 50 years of claiming to be a purely defensive alliance, NATO now finds itself in an offensive war against a country that never threatened any member state. Hunkering down for a long campaign in Yugoslavia, the Western leaders gathered in Washington did their best to justify a war that seems, at best, only tangentially related to NATO's founding purposes. Again and again they challenged themselves to remain vigilant against a new kind of evil more insidious than the Evil Empire. "Have we got an enemy?" asked Portuguese Prime Minister Antonio Guterres in his opening-day speech. "I think yes. No longer a country, a system, an ideology. Our enemy is the rejection by so many in the world of the values of the Enlightenment, of reason, as the fundament of behavior in politics. Our enemy is extreme nationalism, religious fundamentalism, racism, xenophobia, ethnic cleansing." British Prime Minister Tony Blair, meanwhile, insisted that the alliance was no longer simply about ensuring the security of its members. "NATO," he said, "must have a moral perspective and a conscience. We must be willing to right wrongs and prosecute just causes." Not to be outdone, Secretary of State Madeleine Albright opined that the new NATO's "core purpose" must be to defend "basic human decency on European soil." Critics who admonished the West to beware of "mission creep" after the fall of the Iron Curtain saw their worst fears come true at the summit. NATO's mission didn't just creep, it exploded. In the absence of any clear strategic purpose, NATO has morphed from a military alliance to a moral alliance. It is pledged to discourage excessive religion and force people to be decent. If NATO follows through on its promise, the Yugoslavian campaign could be just the first of many ill-defined, ill-conceived military adventures. The perseverance of the lone protester in the shadow of the Kennedy Center would be sorely tried. "Bring Our Boys Home Now," read his hand-lettered sign. He might want to pull up a chair.