Serbia's failure to hand over Gen Ratko Mladic to the International Criminal Tribunal for the Former Yugoslavia has resulted in the suspension of its negotiations with the European Union and plunged its governing coalition into a political crisis.
Finding, arresting and transferring him to The Hague is a necessary condition for dealing with Brussels if that relationship is to develop towards eventual talks on membership of the EU. The enlargement commissioner, Olli Rehn, underlined yesterday that the rule of law must apply and be seen to do so. That is the only basis on which the terrible wounds inflicted by the wars in which Gen Mladic played such a prominent role can be treated and eventually healed. He is charged with responsibility for the Srebrenica massacre in which 8,000 people died and for the prolonged siege of Sarajevo, capital of Bosnia-Herzegovina, which claimed at least another 10,000 victims.
Gen Mladic has been on the run since he was first indicted as a war criminal in 1995. He has been protected by the radical nationalists who sustained the war, and by their allies in the Serbian military and intelligence forces who have resisted handing him over. That this remains a highly sensitive issue is plain to see in the political machinations over the last month in Brussels, The Hague and Belgrade. The EU gave Serbia's prime minister, Vojislav Kostunica, a month's extension of the deadline to hand Mladic over at the end of March after he assured them it would be possible. Clearly he has failed, and his deputy, Miroljub Labus, resigned yesterday in protest.
Should their coalition break up on the issue the consequences could be serious for any future development of the relationship with the EU, since the radical nationalists are ahead in the opinion polls. The death of Slobodan Milosevic in the custody of the tribunal last March has probably bolstered their position. So, too, are looming decisions on Montenegro's future and on the status of Kosovo. In Bosnia-Herzegovina there was a setback last month when its leaders failed to respond positively to a new political plan proposed by the international force there.
The key to political progress in former Yugoslavia is how its successor states relate to Europe as a whole. Political reform in the region has been driven since the end of its wars by the prospect of the EU's eventual enlargement to embrace its successor states. Serbians now face grave choices about where they want this process to go.