From attacking a sovereign state for oppressing a minority to airlifting tents and food to refugees, the NATO alliance finds itself in the midst of a far-reaching transformation as it struggles to surmount the Kosovo crisis.
Founded to defend Western Europe from Soviet invasion, NATO is moving even further from its original purpose with the deployment to Albania of American helicopters, mobile rocket launchers, and 2,000 soldiers to support a widening of the war on Yugoslavia.
And it may not stop there. While President Clinton and his NATO counterparts continue to rule out ground operations, there is a growing expectation that troops will eventually have to be used to repatriate the hundreds of thousands of ethnic Albanians driven from Kosovo by Serbian forces.
The developments have overtaken a debate within NATO over the kinds of missions it should assume in the post-cold-war era. But that does not mean the question is being settled. In fact, some experts warn that even if it prevails in Kosovo, NATO could emerge weaker and more feud-riven from the crisis than when it began its airstrikes two weeks ago.
"The 21st-century NATO is going to have a lot less consensus," predicts Prof. Daniel Nelson, a European security expert at Old Dominion University, in Norfolk, Va.
The debate over NATO's future began almost as soon as the Soviet Union collapsed in 1991. While some experts argued the alliance should be disbanded, the allies agreed not only to maintain the pact, but to admit former Marxist states to avert the reemergence of the age-old European feuds that ignited two world wars this century.
The first new members - the Czech Republic, Hungary, and Poland - joined last month.
The Clinton administration has been pressing its allies to go even further by adopting at NATO's 50th anniversary summit in Washington this month a new "Strategic Concept" that would build on its successful Bosnia peacekeeping operation.
The administration wants the document to embrace new missions to thwart threats that emerge outside NATO's boundaries, such as the proliferation of long-range missiles and biological and chemical weapons in the Middle East. Led by France, many NATO members object, anxious that NATO not become "the world's policeman."
But with the Kosovo crisis exploding at a pace far beyond that anticipated by the US and its allies, NATO is having to expand the scope of its operations without resolving the basic question of future missions.
This transformation began with the first attack by the pact against a sovereign state, launched after Belgrade rejected a US-authored plan to end a Serbian crackdown on ethnic Albanian civilians and rebels in Kosovo. In another precedent, NATO proceeded without the authorization of the United Nations.
The alliance moved further into new territory over the weekend with its decision to aid ethnic Albanians driven into Albania and Macedonia by Serbian forces. NATO officials estimated that as of Monday, the expulsions were approaching 1 million, half of Kosovo's ethnic Albanian majority.
Confronted by Europe's worst humanitarian calamity since World War II, 12,000 NATO troops are now erecting tent cities and delivering food and water to refugee-packed areas on Macedonia's border with Kosovo. American soldiers, meanwhile, have started helicoptering relief supplies into northern Albania. NATO plans to send between 6,000 and 8,000 troops to Albania to help with the relief effort.
The allies also agreed to temporarily admit some 100,000 refugees to relieve some of the pressure on Macedonia and Albania. The largest number is to be taken by Germany, which is accepting 40,000. The Clinton administration says it will take 20,000 ethnic Albanians and house them at the US military base at Guantnamo Bay, in Cuba.
NATO is also stepping up its military involvement, adding to its forces an American naval battle group led by the USS Theodore Roosevelt, a carrier with some 50 strike aircraft. The flotilla, which is moving from the Mediterranean, also includes four cruise-missile-firing ships.
Twenty-four American Apache ground attack helicopters and 18 mobile multiple rocket batteries, accompanied by some 2,000 support and security troops, are to arrive in northern Albania in the next 10 days. The Pentagon says "Task Force Hawk" will be used to supplement airstrikes on Serbian tanks and artillery operating inside Kosovo.
The new forces "will give us the capability to get up close and personal to the [Yugoslav President Slobodan] Milosevic armor," says Pentagon spokesman Kenneth Bacon. But he acknowledges that "close-in engagement is by definition riskier than more distant engagement."
The helicopters are capable of flying in bad weather, which until Monday had greatly impeded allied pilots. The Apaches and the rocket batteries, which can reach almost anywhere in Kosovo, could also be used to support ground troops if they are ever deployed.
Experts say that the missions NATO is now undertaking in Kosovo are the kind the Clinton administration has been advocating the alliance adopt for the coming century. But they also say that the difficulties NATO has encountered so close to its boundaries make it highly unlikely the US will win approval of its call to expand NATO's missions outside Europe.
"Everybody in the [Clinton] administration wanted NATO to go beyond Europe," say Ivo Daalder, a former National Security Council official now at the Brookings Institution in Washington. "That debate is over."