Split over Kosovo independence
The national election was triggered in March, when Mr. Kostunica pulled out of a fragile governing coalition with President Boris Tadic's pro-European Democrat Party (DS). Mr. Tadic was not prepared, as a gesture of protest against Kosovo's independence, to abandon plans to join the European Union.
Kostunica, meanwhile, refused to contemplate further integration without Kosovo. The result was an acrimonious split and the collapse of the government.
In Nis, the speeches made by Radical leaders were full of signs that the concerns of Western countries that nationalist elements may strengthen were justified. "Kosovo is ours," Radical Party leader Tomislav Nikolic said. "We didn't win it in the lottery. It's Serbian by history. European Union? Yes – but not without Kosovo."
The European Union is so anxious to see a Democrat victory that last week they signed a crucial pre-membership accord, the Stabilization and Association Agreement (SAA) with Serbia in an attempt to boost the prospects of the beleaguered pro-Western parties.
But observers warn that because the EU is seen as one of the principal architects of Kosovo's independence, the move could have the opposite effect.
"Tadic is trying to make this election a referendum on the EU – but he hasn't sold the EU to the Serbian population," says James Lyon of the Brussels-based think tank International Crisis Group. "In contrast, Kostunica has successfully defined the SAA as signing away Kosovo."