NEWS ANALYSIS : Defense Ministers Patch Up NATO Unity : Diplomacy: Two-day meeting finds ways to strengthen U.N. force in Bosnia. U.S. softens talk of expanding alliance.

During a two-day meeting ending Thursday, NATO defense ministers did a good job of patching together a sense of unity in an alliance that in recent months has become dangerously divided.

On the crisis in Bosnia-Herzegovina, an issue that has so torn the 16-member North Atlantic Treaty Organization that some feared it could cause irreparable damage, the ministers visibly pulled together to find ways of strengthening the struggling U.N. Protection Force there.

On the delicate subject of extending NATO membership eastward--which drew criticism this month from some European allies that the United States had forced the pace and spooked the Russians--Defense Secretary William J. Perry noticeably throttled back the Administration’s rhetoric.

“There’s no timetable on expansion,” he said at a news conference Thursday before leaving for Moscow. “All of us believe this will take some years.”

And, in case anyone missed the subtleties, an official communique on the meeting stressed “the determination of our alliance to maintain its unity and cohesion.”

But while NATO seems to have recovered its balance temporarily, more trouble almost certainly lies ahead.

Indeed, with all the unknowns in NATO’s future, one of the few certainties is that unity will be increasingly difficult to maintain.

In many ways, NATO faces a reality articulated nearly two centuries ago by the French diplomat Charles Maurice de Talleyrand: Coalitions tend to last only as long as the reason that brought them together in the first place.

With the common enemy--communism--now dead, NATO’s glue has weakened perceptibly.

The foray into Bosnia was an attempt to carve out a new, post-Cold War role for NATO as a peacekeeper in brush-fire wars outside its own member countries. It has been a crushing failure, in part because the alliance has found itself completely at odds with the way the United Nations conducts its business.

But NATO has also suffered greatly in Bosnia because in this post-Cold War era, the interests of its members no longer coincide as they once did.

When President George Bush made a conscious decision to stay out of the way of a collapsing Yugoslavia, it marked the first time since World War II that the Europeans faced a major crisis on their own.

With the forces of seven NATO allies struggling on the ground in Bosnia and the Clinton Administration belatedly eager to punish the Bosnian Serbs from the air but unwilling to commit ground troops, strains within the group were inevitable.

A row between the United States and France late last month over tactics in Bosnia became so bitter that both sides reportedly pulled back for fear of opening a serious, long-term rift.

“Bosnia marks a setback,” noted Edward Foster, a European defense expert at the Royal United Services Institute in London. “We’ve had a clear illustration of how the abstract concept of exporting stability plays out in reality.”

The rift over NATO’s eastern expansion has similar origins: a conviction on the part of Europeans that the United States has waded into an extremely sensitive issue, complicating rather than helping resolve their problems.

The view of one European ally was reflected in a confidential telegram last month from Germany’s NATO Ambassador Hermann von Richtofen to the Foreign Ministry in Bonn warning that the U.S. attempt to push through rapid expansion could turn “into a Pyrrhic victory for the alliance.”

Since that message was leaked to a Munich newspaper, officials from several other European delegations at NATO have commented that it captured their feelings too.

“It’s not the policy itself, it’s the lack of contact, the lack of real consultation,” complained a senior official at NATO, who declined to be identified by name or nationality.

Transatlantic differences are nothing new to NATO. Before the fall of the Iron Curtain, the Americans frequently clashed with their allies. But in those years, agreement always came because of the need to unite against the Soviet threat.

Now that threat no longer exists.

“There is a different international climate and a different America,” said Dominique Moisi, deputy director of the French Institute for International Affairs in Paris. “It is an America much less keen to be involved in Europe. It’s wrong to talk about NATO being terminally ill, but the crisis it faces now is deeper than at any previous time.”