UN Prepares Yugoslav Peacekeeping Role

UNITED Nations diplomats are increasingly optimistic that the war in Yugoslavia at long last may be winding down and that its leaders may be ready to settle their differences politically.

In what is hoped will prove an auspicious start to the new year, United Nations Secretary-General Boutros Boutros-Ghali and the European Community's Lord Carrington have taken key steps in recent days to encourage Yugoslavia to stick with its newest cease-fire and resume the Conference on Yugoslavia peace talks. The presidents of the six Yugoslav republics have agreed to meet informally in Brussels Jan. 9.

Picking up from his predecessor without missing a beat, the new secretary-general is sending 50 top military liaison officers this week to the headquarters and about 10 field offices of the Serbian-led Yugoslav National Army and the Croatian National Guard. The officers, drawn from existing UN peacekeeping operations are, in effect, an advance contingent of peacekeepers.

The job of this new team will be to support and encourage the cease-fire reached in Sarajevo Jan. 2. It is the 15th attempt, but the first brokered by the UN. The UN officers will try to ease communication and resolve differences between warring factions. They will work closely with observers from the European Community who are to monitor what one diplomat calls the "nuts and bolts" of the cease-fire. Glimmer of hope

Mr. Boutros-Ghali decided to send the military team after hearing a report Jan. 5 from Cyrus Vance, the secretary-general's personal envoy to the Yugoslav conflict who has just returned from his fifth mission. Boutros-Ghali says he is acting on an admittedly tenuous "glimmer of hope" that the situation in Yugoslavia may be improving. He issued a full report on the situation Jan. 6 to the Security Council. Though the Council is expected to add its endorsement to his military-liaison plan this week, "We ca n move without it," says Francois Giuliani, spokesman for the secretary-general. Detailed cease-fire plan

The latest cease-fire, reached when Mr. Vance called opposition leaders to an afternoon meeting in Sarajevo Dec. 31 and spelled out the terms, is regarded as particularly promising for several reasons. It is detailed rather than wishful.

Before either side can return fire, for instance, the cease-fire violation must be reported to a liaison office in touch with both sides. Neither side can move any units forward and the other party always must be notified in advance of any troop movement.

The new cease-fire is also closely linked both to an eventual UN peacekeeping operation and to the ongoing political process. "All parties want a peacekeeping operation and they understand that unless they create the conditions, they're not going to get it," says one diplomat long involved in the effort.

After the cease-fire was signed, Vance flew to Portugal, current chair of the European Community, where he assured his longtime close friend Lord Carrington that all parties were willing to continue participation in the Conference on Yugoslavia.

Twenty UN political-military observers led by Ambassador Herbert Okun worked in Yugoslavia in late December to determine political and practical steps to pave the way for UN peacekeepers. Vance has insisted from the start that no UN peacekeepers should be sent in until a durable cease-fire is reached.

The expected contingent of 10,000 or more would be one of the UN's largest and the first sent to Europe. Under the plan all major parties have now agreed to, UN forces would replace the Yugoslav Army in several Serbian parts of Croatia. Unrealistic leaders

Though Serbia has gained most of the territory in the bitter fighting over the last six months since Croatia and Slovenia declared their independence, Serbian troops are said to be tired and their political leaders are being increasingly realistic.

"Even the most passionate Serb nationalists do recognize that they can't possibly hold Yugoslavia together," notes Otto Ulc, a political scientist at the State University of New York at Binghamton. "What they want to do now is ... change the borders so that parts of Croatia will be carved out where Serbs have substantial ethnic representation - and to get to the seacoast." Professor Ulc predicts independence for most Yugoslav republics.