Reluctant as they are to proclaim victory -- yet -- President Clinton and his senior advisers are permitting themselves their first sidelong looks at what NATO has wrought in the Balkans. There is an air among them of having crossed a threshold, or several, in Europe and in the wider world.

Much as the Persian Gulf War brought seismic shifts to that region, to U.S. politics and to the image of America's global aims, the outcome of the war in Yugoslavia will help shape the answers to some of the large questions the conflict has forced upon the international stage. Chief among them are whether a nation's sovereignty over its people and territory can be legitimately violated on humanitarian grounds; Kosovo suggests that it can.

The usefulness of the NATO alliance outside of its historic neighborhood in Central Europe has been cast in a new light, as has the effectiveness of using limited military force to achieve political aims. For the first time, air power alone may have defeated an army in the field.

The emerging peace process in Kosovo will deeply imprint the evolving relationship between the United States and its former adversaries in Moscow, and the future of the Balkan region itself. And whether or not the triumph of Operation Allied Force is sustained, or widely accepted, it could make a debate over America's role in the world a central theme of the 2000 presidential campaign.

Secretary of State Madeleine K. Albright, the first and most insistent voice for the war, sees its outcome as a setback not only for Belgrade, but for the politics of ethnic hatred writ large. She cast President Slobodan Milosevic as the embodiment of the third great evil to afflict Europe this century, and his defeat as a healing portent of full recovery.

"Not only were we fighting Hitler, we were fighting fascism," she said in an interview late Friday. "Not only were we fighting Stalin, we were fighting communism. Now we're not only fighting Milosevic, but we're fighting genocide and ethnic cleansing and crimes against humanity.

"I fully believe that one of the truly important accomplishments of President Clinton's administration is the possibility for the first time in history to have a Europe that is united and free and democratic," she said. "What was missing after we expanded NATO and the end of the Cold War -- the missing piece was the Balkans."

National security adviser Samuel R. "Sandy" Berger cautioned in a White House interview yesterday that "it is very dangerous to overlearn the lesson" of Kosovo. But he and many colleagues, along with friends and critics around the world, are already infusing meaning into an outcome they expect to be "transformative in some sense," as one senior policymaker put it.

Clinton and his advisers see vindication for a doctrine of limited violence for limited aims, the administration's rebellion against the Persian Gulf War standard of "overwhelming force" or none at all. Said one official: "You won't see [retired Gen.] Colin Powell on TV today talking about the Powell Doctrine," which spelled out the concept of overwhelming force. Berger, more politic, averred that "there can be circumstances short of an existential threat to the United States where the use of force is appropriate" and an air campaign may suffice.

Future policymakers in the Clinton administration and probably beyond will cite Kosovo as proof that coercion works, a view about which the U.S. military has had its doubts, and that air power alone, or nearly alone, can defeat a substantial enemy on the ground.

The war's apparent success has already rippled strongly through the waters of the nascent 2000 campaign, and the competition for office abroad as well. Vice President Gore, by this week's consensus, has dodged a grave threat to his nomination and election. Republicans are freshly divided between their outward- and inward-looking wings at a time when foreign policy has been thrust to prominence on the hustings.

There is still a threat that the apparent NATO victory will crumble as the generals seek to implement it on the ground; yesterday there already were reports from the region of possible snags. Yet if Milosevic's seeming surrender holds, Clinton, running for the history books, is "the number one escapee," according to one close adviser: "He doesn't have to make the ground troop decision, which would have been the toughest decision of his presidency. If he had invaded, that would have been his legacy. If not, he would have been held responsible."

Across western and central Europe -- especially in Germany, Italy, the Czech Republic and Greece -- the results of the 73-day bombardment reward NATO governments that took major gambles with their constituencies. Other nations, friendly and unfriendly, have been transfixed by the unfolding test of wills.

If the West's adversaries sought a measure in the conflict of its brawn and stomach, the answers are ambiguous. On the one hand, NATO's use of integrated and standoff combat systems -- what strategists call the "revolution in military affairs" -- overwhelmed a large and capable military force. Yet the very fact of "zero friendly casualties," and the sense among commanders that they were expected to produce a bloodless win, reinforced military anxieties on the brittleness of public support.

Smaller capitals, in particular, may grow anxious about the idea, seemingly affirmed in Kosovo, that the United States, or some international coalition, may intervene in the domestic affairs of a state on humanitarian grounds. When Deputy Secretary of State Strobe Talbott canvassed the Balkans for support, Romanian officials in Bucharest drew some of his aides aside. What exactly, they asked, does Kosovo portend for NATO's attitude toward the restive ethnic Hungarian population in Romania's Transylvanian region?

Such echoes of Kosovo's root conflict abound, in the Balkans and around the world. Leaders who would respond to them with force, said a senior Clinton administration official, now have an object lesson from NATO.

"Certainly any player in Europe who's contemplating the kind of ethnic war that Milosevic made a practice of now knows that one possibility is that thousands of bombs and missiles may set his country back decades," the official said. "The whole world saw that what Milosevic did to Kosovo, yielded what happened to Serbia."

Staff writer John F. Harris contributed to this report.