The Bosnian ceasefire announced yesterday represents the most promising opportunity yet to end a war that has torn apart the former Yugoslavia for the past three-and-a-half years. However, if the truce is to be converted into lasting peace, the Bosnian Muslims, Serbs and Croats will all have to accept limits to their political and territorial ambitions - limits for which none has so far shown much enthusiasm.
Perhaps the main reason for thinking that the ceasefire will work is that, for the first time, military reality on the ground broadly corresponds to the peace proposals.The Muslim-Croat forces and the Bosnian Serbs each hold about half of Bosnia's land, a division of territory that matches the principle at the heart of the peace initiative devised by the US envoy, Richard Holbrooke.
Still, serious matters must be hammered out. The future of Sarajevo, the eastern enclave of Gorazde and the northern area of Brcko are all unresolved, and much uncertainty clouds the relationship between the Muslim leaders and the Bosnian Croats.
The Muslims, supported by the US, argue that Sarajevo must not be partitioned into two sectors, one controlled by the government and the other by the Bosnian Serbs. But the Bosnian Serbs dislike the idea of resurrecting Sarajevo as a functioning capital city, and equally ominously, some Bosnian Croats want a special Croat sector of Sarajevo.
Then there is Gorazde, the last Muslim-held area in eastern Bosnia. If it is to stay part of the Muslim-Croat federation, should it be linked to the Sarajevo heartland by a corridor of land or merely by a road that would be under Serb control?
It is a measure of Bosnian Muslim sensitivities that the US could not persuade the Sarajevo leadership to trade Gorazde for extra territory in central Bosnia. Indeed, President Alija Izetbegovic regards it as a severe injustice that he should be asked to recognise Bosnian Serb control of almost all the Drina valley towns in eastern Bosnia.
The Brcko corridor is a narrow strip of land that connects Serb possessions in eastern Bosnia with Serb-held regions in the north around Banja Luka. Retention of this corridor is crucial to the viability of the Bosnian Serb sub-state envisaged in the US plan, but there is still no accord on exactly how much land the Bosnian Serbs should have around Brcko.
One problem rarely addressed in public by US officials concerns the ambition of some Bosnian Croats to jettison the Muslim-Croat alliance in favour of a de facto union with Croatia itself.
The complete collapse of the Serb position in the Knin Krajina of Croatia, and in western Bosnia, has meant that there are tempting possibilities for the Bosnian Croats to reduce co-operation with the Muslims and form a united front with Zagreb. This would probably not mean a formal Croatian annexation of Bosnian Croat territory, but it could doom the Muslim-led central Bosnian government in Sarajevo to paralysis.
Welcome though the ceasefire may be, it points to a peace settlement that penalises the Muslims without fully satisfying the Serbs and Croats. If it is the only peace available, it is none the less unstable.