NEWS ANALYSIS : No Serbian Role Expected in New Bosnia : Balkans: U.S. says the Serbs are welcome to join Croat-Muslim alliance. But such a move is unlikely.

A U.S.-brokered plan to redesign Bosnia-Herzegovina has been drafted on the assumption that Bosnian Serb rebels who sparked the war two years ago want no part of any new alliance, American officials conceded Monday.

Washington’s acknowledgment that Serbian nationalists are likely to insist on territorial autonomy from the emerging new Bosnia signaled that American officials, who had opposed previous peace plans based on ethnic division, now see partition as inevitable.

“The Serbs will have to decide what they want to do. The federation is certainly open to them,” a senior U.S. official said.

But he said the 52-page constitution put together in 10 days of negotiations at the U.S. Embassy here envisions a two-faction federation--Croats and Muslims--and would have to be rewritten if Serbs unexpectedly agreed to join in.

Another source close to the negotiations said the American strategy in reuniting Bosnia’s Croats and Muslims has been to strengthen their position in the struggle to get Serbian gunmen to withdraw from territory designated for Bosnian government or Croatian control in 18 months of earlier peace talks in Geneva. At those talks, mediated by Lord Owen of the European Union and special U.N. envoy Thorvald Stoltenberg, the three warring factions agreed to a theoretical territorial division.

Under that formula, which American officials here are also using as a partitioning basis, the Muslim-led government would have sovereignty over 33.5% of Bosnia, 17.5% would go to the Croats and 49% to the Serbs, who now occupy 70%.

U.S. officials say they are committed to seeing the Croats and Muslims recover all 51% of territory jointly awarded them in Geneva, although they decline to say what the United States or the North Atlantic Treaty Organization might do to force a Serbian rollback.

Mediators appear convinced that the Serbs will see the wisdom of giving up about one-third of the territory they have conquered in return for a peace settlement that would allow them to annex the rest of their war spoils to neighboring Serbia. Assurances have also been made by the Americans that severe U.N. sanctions imposed on Serbia for instigating the Serbian rebellion in Bosnia will be eased or lifted if peace is restored.

In announcing late Sunday that the Vienna talks had produced a draft constitution, the American diplomat overseeing the talks said the next step will be to work out an overall settlement for Bosnia, which would have to gain the approval of the rebel Serbs.

“Only at that point might one be in a position to say what form this federation might take,” said special U.S. envoy Charles Redman. “Whether it would be expanded to include the Bosnian Serbs, (or) part of Bosnia in another configuration, it’s simply too early to say.”

But the interpretations offered Monday suggested that the U.S. mediators have pressured the Muslim-led Bosnian government into accepting the inevitability of division in exchange for vows of American backing in the bid to free some Serb-occupied territories.

The official emphasized that the main advantage of linking Croatian and Muslim territories and loosely aligning them with neighboring Croatia is that it avoided leaving a landlocked, economically inviable Muslim state sandwiched between a Greater Serbia and a Greater Croatia.

Under the previous partitioning plan mediated by Owen and Stoltenberg, three ethnic ministates would have been carved out of Bosnia, and the Croatian and Serbian provinces would have had the right to secede and join their mother republics.

Bosnian Prime Minister Haris Silajdzic confirmed that Washington has vowed to back his government’s bid to recover Serb-besieged Muslim enclaves in eastern Bosnia but declined to say whether that pledge was given in return for Sarajevo’s capitulation to an eventual partition.

Bosnian Serbs have reacted to the Muslim-Croat reconciliation with cautious hopes that it might speed their secession from the multiethnic republic but also with alarm over mounting Western pressure for an end to their armed rebellion and withdrawal from some of the territory they have conquered.

Yasushi Akashi of Japan, the special U.N. envoy for the Balkans, warned last week that the Bosnian Serbs are feeling “isolated” by the U.S.-brokered agreement. Bosnian Serb leader Radovan Karadzic has warned Washington against its working with Muslim and Croatian adversaries to intimidate his forces.

On Saturday, Bosnian Muslim and Croat military chiefs agreed in a meeting with a former NATO commander, retired U.S. Gen. John Galvin, to merge their separate militias into a single army.

But one U.S. diplomat said the Serbian fears should not compel the West to back down. “Uncertainty can be a positive factor,” said the diplomat, adding that one of the West’s greatest mistakes in the conflict has been to “make all too clear what we weren’t willing to do.”