WHEN it comes to United Nations peacemaking, just keeping warring armies disengaged is usually challenge enough. When it also involves the unprecedented task of organizing a referendum in a remote swath of desert, the job takes on an entirely new dimension.
That is exactly what the UN has been trying to do in the Western Sahara, a former Spanish colony contested by Morocco and a local rebel force known as the Polisario Front. After 17 years of conflict, the two sides have agreed to a cease-fire and a referendum to determine the future status of the territory. But the UN, frustrated by renewed squabbling over the issue of who can vote, has signaled that its patience, while ample, is not inexhaustible.
"Acceptance of this delay should not be perceived as indicating an open-ended commitment on the part of the international community," UN Secretary-General Boutros Boutros-Ghali warned in a recent report.
In the still unlikely event that UN peacekeeping efforts falter, the result could be renewal of the low-level conflict that has already claimed several thousand lives. Collapse could also impinge on the future of Morocco's King Hassan II, a longtime ally of the United States, who has invested huge amounts of financial and political capital to ensure a favorable outcome for Morocco.
"If the peace plan fails, it could have serious consequences for stability in North Africa," warns a report issued last month by the US Senate Foreign Relations Committee. Disagreement on voters
UN peacekeepers, including 29 Americans, were sent to the Western Sahara last September to enforce a formal cease-fire until local residents (Sahrawis) decided whether the territory should become independent or part of Morocco.
But the referendum, which was to have been held last month, has been delayed because of the dispute over voting rights.
Morocco and the Algerian-backed Polisario initially agreed that a 1974 Spanish census should serve as the basis of the voting list, which would be updated to reflect recent demographic changes. But the process was thrown off track when Morocco unexpectedly presented the UN with a list of 120,000 additional names. In addition, Morocco began moving nearly 40,000 prospective voters into tent cities in the territory late last summer, precipitating an end to an informal two-year cease-fire.
Mr. Boutros-Ghali has set a time frame of three months for redefining eligibility requirements. Many observers say it could take far longer. So far, peace is kept
If an impasse is reached, the two sides might have to adopt a whole new approach. Any compromise would almost certainly have to be based on a recognition of Morocco's sovereignty over the region, analysts say.
"Within that framework there's lots of flexibility, including local autonomy for the Western Sahara and possibly even a role for the Polisario," says one analyst based in Washington.
Since the UN force was deployed there have been no exchanges of fire and no deaths on either side. Commanders in the field say they are now positioned to detect preparations for any major attack by either side.
But monitoring the cease-fire has been complicated. Moroccan troops have hindered the movement of peacekeepers and, until recently, blocked supply lines, according to the UN and the Senate report. And the UN force, known by the acronym MINURSO, has had little political support from UN headquarters and has been forced to live in harsh conditions without adequate supplies, the Senate report adds.
"Without the proper tools to carry out its mission, there is little likelihood that MINURSO can maintain an atmosphere of confidence or sufficient credibility to ensure that a free and fair referendum takes place," the report says. "If the present circumstances persist, MINURSO runs the risk of failure."
Under the original UN plan, the peacekeeping force was not to be deployed until the issue of voter criteria was resolved. But former UN Secretary-General Javier Peres de Cuellar reversed the sequence, leaving the force in what the Senate report describes as a "holding pattern" until political questions are resolved.
The dispute over the phosphate-rich Western Sahara erupted after Spain relinquished its former colony in 1975. Citing historical rights going back to the 11th century, Morocco immediately annexed two-thirds of Western Sahara. It occupied the rest when Mauritania, under pressure from Morocco, renounced its claim to the remaining third in 1979.
The takeover was resisted by native Saharans who formed the Polisario guerrilla front and have operated since out of bases clustered around the Algerian border town of Tindouf.
Outspent and outgunned, Polisario has been on the defensive, its forces confined to a narrow strip of land - 20 percent of the disputed territory - isolated behind a fortified 1,200-mile wall of sand and barbed wire erected by Moroccan troops. Polisario forces have also been the victims of a 1988 rapprochement between Morocco and Algeria, which has greatly reduced Algeria's support for the guerrillas. High cost to Morocco
But Morocco has been weakened economically by the huge cost of supporting 120,000 soldiers in the region and by lavish spending to provide free schools, medical care, and housing to win the support of Western Saharans for the eventual referendum. The estimated $250 million spent by Morocco in the territory each year has come at the expense of pressing social needs at home.
The UN force in the Western Sahara is only one of 11 peacekeeping forces assigned to disarm combatants and monitor truces in hot spots around the world.
Since last fall the UN has launched or planned major peacekeeping operations in El Salvador and Yugoslavia in addition to the Western Sahara. UN peacekeepers are also deployed in the Middle East, Africa, and the Asian subcontinent.