BERLIN — BERLIN -- After nearly four years of hatred and butchery in Bosnia, the NATO mission to enforce a peace agreement faces an unholy mix of bad possibilities, an assignment so rich in potential misfortune that it begs comparison to some of the world's most notorious, longest-lived trouble spots.
In the divided cities of Sarajevo and Mostar, Bosnia has two potential Beiruts in the making.
With three rival religions in the mix, the clash of faiths is even more complicated than the deadly Catholic-Protestant "troubles" of Northern Ireland.
With hundreds of thousands of refugees clamoring to go home, there are elements of Rwanda and the Middle East.
And with Bosnia's rugged hills and dense forests, the country offers the guerrilla paradise of Afghanistan or Vietnam.
Yet, despite the aptness of each comparison, NATO and U.S. troops could also carry out a virtually bloodless year of military occupation.
"It could go smoothly and everyone could come out in 12 PTC months," says Paul Beaver, an analyst with Jane's Defense Weekly.
"However," Mr. Beaver adds, "we are talking about the Balkans, and it is a place where historically there has always been trouble."
Whatever the case, the mission will begin soon, almost abruptly so, now that the leaders of Bosnia, Croatia and Serbia have initialed a formal agreement.
Unless the U.S. Congress finds some way to stop it, senior NATO officials say deployment of 20,000 American troops would begin within a few days of a formal signing ceremony early next month in Paris.
NATO officials and independent analysts who have been briefed on NATO's plans say the force of about 60,000 soldiers will divvy up the country roughly the way the United States, Great Britain, France and the Soviet Union divided post-World War II Germany.
About 25,000 of the soldiers probably will be based within Bosnia's borders, both in the Muslim-Croat dominated areas and in the territories controlled by the Bosnian Serbs.
The rest will mostly be in neighboring Croatia and in the Serb-dominanted remnant of Yugoslavia. Some would be stationed in Hungary to help supply and support the operation.
The American occupation zone will be in eastern Bosnia, with forces based in the northeast city of Tuzla. The British will cover ,, western Bosnia from a base in the city of Tomislavgrad; the French will cover southern Bosnia from a headquarters in the capital city of Sarajevo.
The operation's field commander, based in Sarajevo, will be U.S. Admiral Leighton Smith, the NATO regional commander out of Naples.
Serving directly under him will be British Lt. Gen. M. J. D. Walker, while the field commander for the U.S. headquarters in Tuzla will be Maj. Gen. William L. Nash.
All will be ultimately accountable to the overall commander at NATO headquarters in Brussels, U.S. Gen. George Joulwan.
The toughest aspect of the American assignment will likely be in policing the front lines near the town of Brcko, about 25 miles northeast of Tuzla. The town is part of a narrow choke point along a Serb supply corridor to the Serbs' holdings in western Bosnia.
Only a few miles wide, the corridor near Brcko has been bitterly contested throughout the war, a scene of fierce offensives by all sides.
It also proved to be one of the most difficult subjects during the peace talks, with Serbia demanding that the corridor be widened.
Bosnian officials said the issue is to be submitted to arbitrators during the course of the next year.
Another tense spot that will come under American jurisdiction is the town of Doboj. About 30 miles northwest of Tuzla, it was the scene of some of the last fighting before the mid-October cease-fire that preceded the peace talks, as the mostly Muslim army of the Bosnian government captured strategically important ground.
Tuzla itself has remained under the control of government forces throughout the war, and the city is overflowing with more than 100,000 Muslim refugees from other parts of the country.
Until a government offensive during the past few months, the city had only tenuous road connections to the rest of the country. Now there are reliable paved roads connecting the city.
But even more attractive to the Americans is Tuzla's military airfield, which will be used to fly in most of the U.S. equipment, troops and supplies.
If patrolling the front lines goes smoothly, the biggest headache for American forces could be in controlling the 2,000 Russian troops that will also be serving in the area.
The Russian forces -- which have refused to come under NATO control, but have agreed to take orders from a U.S. commander -- have become notorious during the years of the U.N. mission for becoming involved in smuggling and black marketeering while serving in Bosnia.
They have also allegedly showed favoritism to Serb forces.
Sarajevo was envisioned by some analysts as an assignment for all three of the main NATO partners, although much of the final mandate was to be determined by the fine print of the peace agreement.
Rounding out the rest of the NATO forces will be the troops from more than two dozen other countries, including some from non-NATO members Poland, Slovakia and Czech Republic.
And the most interesting participant will be Germany, whose troops last marched here as conquerors during World War II. Chancellor Helmut Kohl has pledged up to 5,000, although none will used in possible combat roles.
The first troops to arrive will set up headquarters and get communications up and running. But thanks to the heavy British and French presence in the current U.N. operation, plenty of the NATO structure is already in place.
A British engineering unit has also been at work in the country for more than three years, performing such tasks as building a vital mountain supply road out of a old goat path.
U.S. planes have also managed to complete much of the necessary reconnaissance during their patrols for NATO during the past several years.
But because many of the NATO mission's tactical details depended on the final language of the peace agreement, NATO planners will still have much to do in these last few days before deployment.
"We're going to see some serious problems in terms of tactics," Mr. Beaver said, "such as: how to police, how to sort out [the warring sides], how much force to use.
"There are going to be renegades. There are going to be people on all three sides who will want to shoot."