NEWS ANALYSIS : The Fine Line Between Success, Failure : Bosnia: NATO appears to have scored several victories. But the war is not over yet.

When U.S. warplanes swooped over this dying capital on Aug. 30, Sarajevans rejoiced, buoyed by the hope that NATO had come to the rescue and would bomb their nemesis, the Bosnian Serbs, into submission.

But the largest combat operation in NATO history carried with it a far more complex agenda of goals, stated and otherwise.

Sixteen days after the campaign began, judging its success is equally complex.

The sustained use of North Atlantic Treaty Organization air power appears to have already altered the military and political equations governing the Bosnian war. It has revived at least the prospect that the Western alliance can work effectively. It has made this besieged city a safer place by blunting the Serbian offensive on U.N.-designated “safe areas”--even though it has failed until now to achieve its primary stated goal: forcing the withdrawal of Serb heavy artillery from a 12 1/2-mile ring around Sarajevo.

“NATO has shown it’s not a paper tiger, but it’s also shown it can’t control everything,” said Heinrich Vogel, head of the Federal Institute for Eastern and International Studies in Cologne, Germany.

Following on the heels of a ground offensive launched by Croatian forces that defeated the Croatian Serbs, the air campaign also appeared to shock the Bosnian Serbs into making some concessions on the diplomatic and military fronts. At the same time, punishment seemed only to steel the resolve of the Bosnian Serb army commander, Gen. Ratko Mladic.

Mladic withstood tons of bombs for more than two weeks and refused to budge, making a mockery of Western might. As NATO destroyed Serbian air defense radar, ammunition dumps and bridges, Mladic continued to refuse to remove his big guns from the edges of Sarajevo.

U.N. officials said Mladic was able to resist partly because the stakes--losing his control over Sarajevo--were so high. Furthermore, limitations placed on targeting and the NATO order to avoid civilian casualties kept pilots focused on a narrow range of isolated targets, avoiding many roads, factories and the civilian areas where the Serbs hide mobile weapons, such as light mortars and light artillery.

“This is a limited military operation, with limited military gain,” said Lt. Col. Chris Vernon, U.N. military spokesman in Sarajevo. “A blank check was not signed.”

Of an estimated 3,300 sorties flown over Bosnia, only 750 were conducted by actual attack aircraft, according to NATO’s Southern Command headquarters in Naples, Italy. And some of these planes were forced to return without dropping bombs because of poor weather.

A main target, the Bosnian Serbs’ integrated air defense system, was hurt but not destroyed, as were communications--an accomplishment likely to be of enormous help in case of a wider campaign or a U.N. withdrawal.

On another level, however, significant damage has apparently been done to the ability of the Bosnian Serb army to wage war, something that U.N. officials pointedly said was not their aim. Thus, the Bosnian Serb superiority that has prevented a negotiated end to the conflict was reduced.

Serbian losses have come not so much from the destruction of ammunition or artillery positions around Sarajevo as from a sharp reduction of their mobility--a capability crucial to the Bosnian Serbs, who have held 70% of Bosnia-Herzegovina largely because they have managed to move their over-stretched infantry forces quickly and effectively from one crisis spot to the next.

In just the past week, according to U.N. military sources, the Serbs lost to Bosnian and Croatian forces about 7% of the Bosnian territory they had held, virtually unchallenged, since 1992. Whether or not this was a tactical withdrawal in western Bosnia, as some analysts suggest, the Serbs were clearly suffering from reduced mobility. By the same token, it is unlikely that the damage to the Bosnian Serb army is permanent.

“His [Mladic’s] supply lines are not so long,” a U.N. intelligence analyst said. “He could resupply and be at pre-bombing capacity in five days.”

If the air campaign has weakened the Serbs, even indirectly, then it has also emboldened the Muslim-led government’s army and its Croatian allies, which may choose to launch additional offensives and send the battlefield into greater chaos.

“Keeping them [Bosnian and Croatian forces] back has become the task of the day,” Vogel said.

European analysts suggested that any reduction of Bosnian Serb military power would almost certainly erode the rebels’ recalcitrance at the negotiating table, and that seemed evident in their willingness to be represented in talks by Serbian President Slobodan Milosevic.

Milosevic had previously been unable to force his onetime proteges to accept earlier, favorable peace deals.

“We may be able to end up with a [peace] agreement that is still awful compared to what could have been attained in 1992, but it will be less dishonorable than would otherwise have been possible,” said Francois Heisbourg, a former head of the International Institute for Strategic Studies in London who also served as a French Defense Ministry adviser. “We’re still going to recognize ‘ethnic cleansing.’ ”

Heisbourg likened the NATO strikes to a political message being sent to the Bosnian Serbs--a message similar to that sent by U.S. President Richard Nixon to the North Vietnamese in 1972 with his bombing of Hanoi: Either accept a politically advantageous peace settlement or go on being bombed.

Indeed, with the Serbs forced into negotiations, an initial agreement reached in Geneva last week set the framework for more realistic talks than in the past.

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But the agreement also achieved what many Bosnians and the West had hoped to avoid: a division of Bosnia roughly along ethnic lines. It effectively rewarded the Bosnian Serbs’ previous aggression.

“On the whole, it was a wash,” said Patrick Glynn, a Bosnia expert at the conservative American Enterprise Institute in Washington. “The Serbs saw it as a confirmation of the strength of their own position.”

In the Geneva agreement, the Serbs enjoyed recognition when the foreign ministers of Bosnia, Croatia and the rump Yugoslavia agreed to a partition of Bosnia, with one of the halves named Republika Srpska--the Bosnian Serb Republic.

The Serbs also, for the first time, agreed to a territory split in which 51% would go to a Muslim-Croat federation and 49% to the Serbs.

The conventional wisdom among Western European sources is that political pressure and a lack of new, acceptable targets will probably bring the air strikes to a complete close within the next two weeks, no matter what the Bosnian Serbs do.

Even before NATO on Thursday announced a temporary halt to the air strikes, growing political pressure from Moscow and a resistance within the alliance itself to any escalation of the present campaign was beginning to restrict NATO’s maneuverability.

No matter how NATO’s involvement in Bosnia ends, the operation has already restored badly needed credibility--both in the alliance’s ability to act and in the larger transatlantic relationship.

“It’s been a plus for Bosnia when you consider the alternatives, and it’s been a plus for the Americans because it’s shown that the United States remains the only power that can really move events,” Heisbourg said.

“It’s also been a plus for NATO, although NATO has been only a convenient instrument in all this,” Heisbourg added.

If the air campaign succeeds and the Bosnian Serbs agree to a viable peace, NATO will get the credit, and the bombings will become a model for future peacekeeping.

If the air campaign backfires, NATO will end up with much of the blame, and critics will raise questions anew about whether there is any role for the alliance now that the Cold War has ended.

Indeed, to some analysts, the episode only underscores what critics have been saying about the limitations of air power: Bombing can do much to knock out key targets, but it cannot always force a victory--or a peace.

Wilkinson reported from Sarajevo, Marshall from Brussels and Pine from Washington.