1 Almost four years into the bloodshed that first ripped apart the old Yugoslavia, a second, wider wave of war threatens.
2 In coming weeks, mediators either will be able to build on brittle truces in Bosnia and Croatia or watch war engulf both simultaneously for the first time since fighting started between Serbs and Croats in spring 1991.
3 Concurrent war in both states would produce a military and political tangle even more complex than the conflicts that so far have defied solution.
4 It almost certainly would mean withdrawal of tens of thousands of U.N. peacekeepers in a hazardous operation backed by U.S. and other NATO troops. It also could mean conflict spreading to other parts of the volatile Balkans.
5 Outsiders -- especially the United States -- are pressuring local leaders in an effort to prevent war from spreading. In Bosnia and Croatia, Washington is signaling that there can be no final settlement without the support of the republics' Serb minorities.
6 This has angered Bosnia's Muslim-led government. But Washington is also trying to shore up the government's troubled federation with Bosnia's Croats as insurance against the Serbs getting, or taking, too much.
7 In Croatia, Washington is a key player in foreign efforts to prevent a new Serb-Croat war that could erupt if 12,000 U.N. peackeepers leave when their mandate ends on March 31, as President Franjo Tudjman insists.
8 Local leaders have also put out feelers for peace that France would like to explore at a proposed European conference attended by leaders of Croatia, Bosnia and Serbia.
9 But almost four years of fighting have created their own logic.
10 The aggressive nationalisms of Tudjman and Serbian President Slobodan Milosevic launched the war. Stoking deep fears, they convinced Serbs and Croats that the ties of blood counted for more than decades of coexistence.
11 Many people who have lost homes, loved ones and livelihoods in the name of nationalism are weary of war, but see little incentive to reach peace.
12 Bosnia's Muslims put no faith in outside powers to regain the 70 percent of Bosnian territory now held by Serbs. They have some trust in their army, now better equipped and trained than at the outset of Bosnia's war in 1992. Travelers to central Bosnia report preparations for more war when a four-month truce runs out May 1.
13 In Croatia, the U.N.-patrolled cease-fire that ended six months of Serb-Croat war in January 1992 still holds. But Tudjman wants the peacekeepers out, blaming the U.N. for cementing the Serbs' hold over one-third of Croatia while doing nothing to disarm them or return Croat refugees to their homes.
14 Although Tudjman claims war won't break out if the U.N. troops leave, Croatia's Serbs have already cut all ties negotiated with Tudjman and will fight if attacked. They have a promise of support from Bosnia's Serbs.
15 Already in Bihac, Bosnia's northwestern tip, Serbs from Bosnia and Croatia are making common cause in fighting against government troops.
16 In all this, the president of Serbia, which dominates the new Yugoslavia, has been silent. Milosevic clearly is not anxious to help either the Croatian or Bosnian Serbs whom he incited and bankrolled into war. He now wants to end international sanctions imposed on his country for fomenting that war.
17 Even if some solution is found for Croatia, Bosnia would remain at war. A deal between Croatia and Serbia to settle the conflict in Croatia would revive the Bosnian government's fears that the Croats and Serbs, with the world's connivance, simply will divide Bosnia between them.
18 As it marks the 50th anniversary of the end of World War II, Europe cannot afford too much self-congratulation. It must brace for more war in its midst.
19 EDITOR'S NOTE: Alison Smale, the AP bureau chief in Vienna, has covered eastern Europe and the former Soviet Union since 1983.

It almost certainly would mean withdrawal of tens of thousands of U . N . peacekeepers in a hazardous operation backed by U . S . and other NATO troops . It also could mean conflict spreading to other parts of the volatile Balkans .
conflict spreading to other parts
Why would it mean conflict spreading to other parts of the volatile Balkans?