NEWS ANALYSIS : U.N. Session Seeks New Lineup : Diplomacy: Underlying the Security Council agenda is a fundamental question: Who will exercise global leadership?

A little more than a year ago, amid the turmoil of the Persian Gulf War, President Bush began talking hopefully of a “new world order”--a system of international understandings that could restore stability and prevent future conflicts from breaking out.

Bush, whose style does not run to high-flown phrases, abruptly dropped the slogan as soon as the war was won. “People were trying to read too much into it,” one of his aides complained.

But the search for a new world order has continued, and this week it will focus on an unusual summit meeting of the United Nations Security Council, a session that will join Bush and the leaders of 14 other countries, including Russia, China, Japan, Britain and France.

The one-day meeting at U.N. headquarters on Friday has been called everything from a political gimmick to an important opportunity for agreeing on new mechanisms for promoting peace. But no matter how it turns out, the session already reflects the new realities of power in a world that is no longer dominated by the two superpowers of the Cold War.

“It’s symbolic of a world that isn’t bipolar but is also not a simple unipolar world run by the United States,” said Joseph S. Nye Jr., a professor at Harvard University’s John F. Kennedy School of Government who has written widely on global power. “It’s symbolic of a world in which we are the biggest power, but we cannot do things alone--we need to leverage our power to get things done.”

It is telling, Nye and others said, that the U.N. summit was organized not by the Bush Administration but by Britain, the current chair of the Security Council. That is partly because British Prime Minister John Major is running for reelection and wants to appear in a role of world leadership, but it also reflects an increasing willingness by Western European countries, including Germany and France, to take the diplomatic initiative.

And it is noteworthy that the U.N. meetings were arranged to enable Japan’s Prime Minister Kiichi Miyazawa to participate--even though his country holds only a temporary seat on the Security Council, not one of the five powerful permanent seats held by the United States, Russia, China, Britain and France.

“We’re thinking in terms of a Big Six now, not a Big Five,” said a British diplomat involved in preparations for the meeting. The other temporary members of the Security Council, including many with little diplomatic clout, were invited as well, but the main talks will be among the six major powers, British and U.S. officials said.

The meeting will also mark Russia’s inheritance of the great-power mantle once held by the Soviet Union and give the other leaders a chance, as a British official delicately put it, “to welcome Boris Yeltsin into the club.”

The issues on the summit table will include a declaration of the great powers’ commitment to “collective security” through the United Nations, an affirmation of the importance of U.N. peacekeeping forces and a pledge to work together against the proliferation of nuclear and chemical weapons.

But underlying that formal agenda is a more fundamental question that may take years to answer clearly: Who will exercise global leadership in a world with no dominant powers?

Instead of leadership by one or two superpowers, many scholars and government analysts predict the evolution of what some call “collegial power”--a loosely structured world in which leadership is shared among several key nations in different combinations depending on the nature of the issue.

On economic issues, leadership is likely to gravitate to a financial Big Three: the United States, Europe and Japan. On issues of military security, the United States is still likely to take the lead, as it did during the Gulf War--but with support from Russia, France, Britain and other countries willing to commit forces to joint police actions abroad.

“Power is clearly going to be more collegial,” said Michael Mandelbaum, a scholar at the Council on Foreign Relations in New York. “But we don’t know how that’s going to work yet. We can see bits and pieces but not the whole picture.

“The U.N. is going to be more important, but it won’t work in every case,” he added. “The Security Council was made up primarily for the powers that won World War II; it doesn’t include either Germany or Japan (as permanent members). An organization that was configured for World War II can’t be expected to lead us into the 21st Century.”

One thing is clear, several scholars said: The United States will have a more difficult time acting as a world leader--but, paradoxically, it will remain the most logical claimant to that role.

“America is the only remaining superpower, but even if the United States is No. 1 we aren’t going to be able to do things without the help of others,” said Nye. “In the Gulf War, we couldn’t have put troops on the ground without the endorsement of the U.N. In the former Soviet Union, roughly 80% of all foreign aid is coming from countries other than the United States.

“On economic issues, Europe and Japan are our equals,” he said. “And on a lot of issues, we’re going to need much broader support than from just Europe and Japan. Issues like non-proliferation and environmental problems will need cooperation from almost every country.”

“U.S. leadership has been, in part, a product of crisis,” said Michael Vlahos, a scholar at the Center for Naval Analyses, a think tank affiliated with the U.S. Navy. “In the crisis years of the Cold War, the rest of the free world accepted U.S. leadership. The same thing happened in the Gulf War. . . . But if you accept the idea of a world that now revolves around economic issues, there’s no way the United States is functioning as the leader.”

Nevertheless, last week’s U.S.-led conference on aid to the former Soviet Union demonstrated that the United States can still play a key leadership role, even when others are spending more money.

The conference was devised hurriedly, and partly for domestic political reasons, to shield the Bush Administration from charges that it was doing too little for Russia and its neighbors. Bush, embroiled in a tough reelection campaign centering on domestic economic issues, hesitated for several weeks before deciding to address the meeting--hardly the image of dynamic global leadership.

But even some European diplomats who initially complained that the United States was offering a conference instead of a real aid program acknowledged last week that the meeting had been useful--and, tellingly, that no other country could have convened it.

“They complain that the American position is ‘we have the ideas, you sign the checks’ . . . but they’re still looking for American leadership,” said Harald Malmgren, a former U.S. trade negotiator. “The Germans want someone else to take the lead. The Japanese don’t feel ready to do it. The British and the French don’t have the clout.”

Still, diplomats noted, Japan and Europe quietly asserted that they will hold a major share in leading the effort to transform the former Soviet republics, deciding that each country will host a follow-up conference to chart the next steps. One meeting will be held in Japan, another in Portugal, the current European Community chair.

A wild card in the new global lineup is the role that will be played by Russia, still the second-largest nuclear weapons power.

For the immediate future, senior U.S. officials said, Yeltsin’s Russia is no longer a global power, only a regional power.

But over the long run, Russia could rise again. And Moscow’s still-formidable military machine makes the U.S.-Russian relationship almost as important to world peace as the U.S.-Soviet relationship was during the Cold War.

For that reason, one senior official said, Bush and his aides are focusing on Yeltsin’s one-on-one meeting with the President at Camp David on Saturday.

In advance of that meeting, a former Pentagon official has offered an audacious suggestion: a formal U.S. alliance with the Russian military.

“By working with the military, we can help stabilize Russia and give them a mission in which the West is not an enemy,” said Fred C. Ikle, a conservative who served as undersecretary of defense under President Ronald Reagan.

He said the U.S. and Russian armed forces could work together not only on nuclear arms control but also in joint actions to deter or repel aggression around the globe.

“They can play a global role in partnership with us,” he said. “It would help restore their pride. It could help forestall a nationalist reaction in Russia . . . and it would be a very powerful deterrent to others.”