NEWS ANALYSIS : Evenhandedness Gets It Nowhere, So U.N. Puts Squeeze on Croatia’s Serbs : Balkans: Sanctions against Yugoslavia are linked to resolution of its neighbor’s standoff. Belgrade could be forced to cut ties to rebels.

After two years of getting nowhere with evenhandedness in the Balkans, the United Nations has undertaken a risky change of course at U.S. insistence by seeking to isolate and undermine nationalist Serbs.

But even supporters of the new approach concede it may prove to be a catalyst for further conflict rather than a deterrent, as both Serbs and Croats are now poised for another round of war.

When the U.N. Security Council this week approved a six-month extension of its peacekeeping mandate here, it bowed to Croatian government demands for more aggressive measures against Serbian separatists who seized one-third of Croatia in 1991 and declared it the independent Republic of Serbian Krajina.

The tougher mandate acknowledges Croatian sovereignty over the disputed region and makes lifting of U.N. sanctions on the rump Yugoslavia composed of Serbia and Montenegro contingent on resolution of the territorial standoff in this republic.

Because that linkage promises to pressure Belgrade into ceasing all support for the Krajina insurgents, the turnaround in U.N. policy was greeted with jubilation in this Croatian capital.

“This is a success of Croatia’s diplomacy,” Deputy Foreign Minister Ivo Sanadar declared in an interview.

Some Western diplomats, particularly Washington envoys, see the new U.N. approach as a long-overdue departure from the practice of treating the conflicts in Croatia and Bosnia-Herzegovina separately rather than as related parts of a regional crisis that will never be resolved piecemeal.

“What has shifted is the whole international attitude toward Croatia, in particular Washington’s attitude. We took the lead on this issue,” U.S. Ambassador Peter Galbraith said of the revised peacekeeping mandate. “What we really had was a policy community in Washington and elsewhere completely focused on Bosnia and ignoring the fact that the war in Yugoslavia began in Croatia and that there would not be peace without a settlement in Croatia.”

A Serbian rebel attack on the outskirts of Zagreb with Scud-type missiles in early September jolted the international community into remembering that a U.N.-brokered peace plan for Croatia has yet to be implemented almost two years after its drafting.

The previous mandate for the U.N. Protection Force offered no real incentive for the Serbian rebels to disarm and re-integrate with the rest of Croatia. On the contrary, U.N. officials concede privately, the deployment simply froze the status quo and freed Serbian troops to turn their gun sights on Bosnia while the United Nations protected their spoils in Croatia.

The strengthened mandate has been denounced by Belgrade. Yugoslav Foreign Minister Vladislav Jovanovic complained to the Serbian-run Tanjug news agency that the Security Council was “singling out Yugoslavia” and giving Croatia license to continue aggressive forays into the Serbian-held territory under U.N. protection.

But senior U.N. officials here fear that isolating the radical Serbian rebels in Krajina and siding with a Zagreb regime whose democratic credentials are still in question may push the Serbs to take desperate measures.

Krajina Serbs reacted with “immense hostility” to news of the mandate revision, said the U.N. peacekeepers’ deputy chief, Cedric Thornberry.

He described the Krajina Serbs as “resigned to the fact that they are going to have to fight another war.”

The first salvos have already been exchanged, with Krajina Serbs retaliating for a recent government massacre in the village of Medak by pounding Croatian towns on the Adriatic Sea coast with more than 1,000 artillery rounds on Monday afternoon alone, Thornberry said.

U.N. peacekeeping patrols also have documented massive buildups of troops and military hardware in the volatile Dalmatian hinterland around the rebel stronghold of Knin and in U.N.-patrolled areas in eastern Croatia, said Shannon Boyd, a spokeswoman for the U.N. troops.

What she described as an “alarming” movement of war machinery prompted the mission commander, French Gen. Jean Cot, to appeal earlier this week for restraint.

There has been no formal reaction from rebel leaders in Knin to the mandate revision, but both military and political analysts predict the Krajina Serbs will be pushed to desperate extremes once fuel, food and arms cease flowing from their patrons in Belgrade, the Yugoslav and Serbian capital.

Serbian President Slobodan Milosevic is widely accused of playing the leading role in fomenting the Balkan bloodshed by arming Serbian rebels in Croatia and Bosnia and instigating the aggressions that have captured huge swaths of territory in both republics. But Milosevic has in recent months made clear his desire to have U.N. sanctions lifted by cooperating with U.N. resolutions to end the conflict.

But many fear Belgrade has little influence over the Krajina rebels. And if Milosevic cuts them off, the Serbs in Croatia may see an all-out battle for independence as their only option for survival.

At least 10,000 died during the 1991 war in which Krajina Serbs, backed by the Yugoslav federal army, seized one-third of Croatia. More than 200,000 Croats were made homeless when the victorious rebels applied the war’s signature act of “ethnic cleansing.”

It was Belgrade’s support for a similar Serbian rebellion in Bosnia that prompted the U.N. Security Council to impose sanctions on the remains of Yugoslavia in May, 1992.

The U.S. push to tie sanctions against Yugoslavia with the ongoing conflict in Croatia is being cast by some Clinton Administration officials as a second chance to ease the Balkan crisis after letting European allies derail a U.S. campaign to quash Serbian aggression in Bosnia with punitive air strikes.

When European members of the North Atlantic Treaty Organization refused to support the Administration’s drive to intervene on behalf of the Muslim-led Bosnian leadership, Western mediators were left powerless to force a negotiated solution.

A plan for dividing Bosnia was drawn up by Serbian and Croatian rebels, but failed to win endorsement by the Sarajevo government last week.

“There is no doubt the posture we took in Bosnia was to distance ourselves from the negotiations,” one Administration official explained. “We never presented a plan and we never endorsed their plan. . . . In this case, we’ve been significantly identified . . . as the party taking the lead on linkage (of sanctions with a Croatian solution).”

But he too acknowledged the risk of provoking the Krajina Serbs by breaking their supply line while offering them no hope of winning concessions from an emboldened Croatian government.

“I think the political leadership may very well be willing to go down in flames,” he said of the Serbian rebels.

Some senior U.N. sources, who decline to be named while criticizing the Security Council, contend the international community should have bowed out of the Balkan conflict when it had a chance this week.

“We should never have come. We have never had the means to do the job and we still don’t,” despite the revised mandate, one U.N. official said.

Another top figure in the peacekeeping force said there had been strong sentiment for a pullout, but that Western countries keen on creating the impression they are engaged in resolving the Balkan crisis opposed such an obvious admission of defeat.