Serbs will decide whether the lure of European Union membership outweighs their anger over the Western-backed secession of Kosovo when they vote in a parliamentary election on Sunday.
The country is divided and the two frontrunners, the nationalist Radical Party and the pro-Western Democratic Party, will have to woo smaller parties to form a coalition.
"It's uncertain whether the pro-Western parties will be able to combat the powerful rhetoric of the nationalist parties," said Dragana Ignjatovic, analyst for business intelligence firm Global Insight.
"The election will be pivotal in deciding the pace of Serbia's European integration in the coming years."
Polls open at 7am (5pm NZ time) and close at 8pm (6am Monday NZ time).
The Radicals say that in the eight years since the fall of autocrat Slobodan Milosevic, acquiescence to the West and harsh market reforms have brought Serbs only humiliation and poverty.
They want to put EU membership on ice, look elsewhere for investment and trade, restore national pride and push Serbia's claim to their former Kosovo province which declared independence, with EU support, in February.
The Democrats say joining the EU is the only way to attract much-needed investment, create jobs and raise living standards that suffered in the isolation of the Milosevic era, when Serbia was a pariah for its role in the Yugoslav wars.
They have tried to combine firm opposition to Kosovo's secession with offering a hand of friendship to the Western countries that recognised it.
EU anxiety
Because neither of the two main parties is likely to win outright, outgoing Prime Minister Vojislav Kostunica is the probable kingmaker.
He has moved closer to the Radicals' position over Kosovo and is unlikely to renew his alliance with the Democrats of President Boris Tadic, whom he accuses of selling out to the EU.
The West and other Balkan states are watching anxiously, because if Radical leader Tomislav Nikolic and Kostunica form a ruling coalition, the return to nationalism will certainly have a ripple effect. Nationalist moves to partition Kosovo, which has a large Albanian majority, and annex its Serb minority could harden Albanian separatist feeling in southern Serbia and Macedonia, and encourage Serb separatists in Bosnia.
The EU has made its preference very clear by offering Serbs a pre-membership pact and a visa facilitation deal that are both implicitly conditioned on a Democrat win.
EU officials say that if the nationalists come to power, Serbia's progress to membership would face long delays.
"The EU cannot influence the election outcome. We wish Serbia would become a member of the EU as soon as possible," said Foreign Minister Dimitrij Rupel of Slovenia, which holds the revolving EU presidency.
But if the Serbs do choose the Radicals, the EU "will talk with the representatives of the Serbian nation", he added.
Some 6.7 million people are registered to vote, including the defiant Serb minority in Kosovo.
