The victory of Serbian nationalist Tomislav Nikolic in presidential elections Sunday could break up an already agreed pro-EU cabinet of his rival Boris Tadic and the Socialists, analysts warned.
After parliamentary polls on May 6, Tadic reached a deal with the third political force, the Socialist party founded by late strongman Slobodan Milosevic, and now led by Ivica Dacic. The parties were coalition partners in the outgoing government.
After his surprise win Sunday Nikolic is expected to offer the mandate to form a government to his Serbian Progressive Party (SNS) which came first in the parliamentary election with 73 deputies in the 250-seat assembly.
According to the Serbian constitution, the future prime minister should come from the party or coalition which has the backing of the majority of deputies in the assembly.
Analysts insisted that the Socialists' support was now decisive in forming the future cabinet.
"Everything now depends on the Socialists' decision whether they will stick to the deal they have made" with Tadic's Democratic Party (DS), said analyst Vladimir Todoric.
During Milosevic's rule in the 1990s -- years of deadly conflicts in the former Yugoslavia and of Serbia's international, political and economic isolation -- Nikolic and his party had been allied with the Socialists.
Despite Nikolic's win, the key to Serbia's stability lies in its future government, analysts agreed.
According to the constitution, the president has a largely ceremonial role, with the government effectively running the country.
"It is the government's role to draw up and implement the political decisions of the country," commentator Slavisa Orlovic said.
Analyst Dejan Vuk Stankovic warned that Nikolic would try to "change current political arrangements" between the Democrats and the Socialists.
"The talks on the future government will depend on those who have negotiated it so far," he said.
Before the results were announced, Socialist leader Dacic, who has managed to distance the party from Milosevic's legacy, said the "condition for our coalition (with the Democrats) is not a victory in the presidential polls".
And Dusan Bajatovic, a top Socialists official, said late Sunday the deal to form the government could go on as agreed.
"There is no reason to change that deal now. The division of power should not be bad for the democratic process in the country," Bajatovic said.
Commentator Orlovic said Serbia had already experienced "cohabitation" when Tadic became president in 2004, when the government was run by conservative nationalist Vojislav Kostunica.
"Tadic was weaker at the time of cohabitation between 2004 and 2007 than from 2008 onwards when his party led the government," Orlovic said.
But sociologist Vladimir Vuletic insisted that even with a government coalition led by Tadic's DS Serbia would face a "serious crisis".
"It will be important to see whether politics will be marked by tensions and disagreements between the president and the government," Vuletic said.
Nikolic, who vowed to keep Serbia on its European path after Tadic had brought it to EU candidacy status in March, said he would cooperate "with everyone in Serbia".
"I want to be a president of all citizens. Serbia must develop its economy, we have to get rid of poverty, we must start working," Nikolic said in his victory speech.
Analysts said the low turn-out of 46.7 percent of the votes boosted Nikolic as only those who wanted change came out to vote.
"This was an electoral earthquake, a totally unexpected result," said analyst Slobodan Antonic, pointing to pre-election surveys predicting a comfortable win for Tadic.