FACTBOX: Serbian PM Kostunica, a political acrobat

(Reuters) - Vojislav Kostunica was due to be sworn in for his second term as prime minister of Serbia late on Tuesday, heading a coalition government that is finely balanced between his moderate nationalist party and its pro-Western allies.

Here are some facts about the former law professor:

* A little-known figure before 2000, he was chosen by a divided opposition bloc and backed by the West as a modest, untarnished challenger to late autocrat Slobodan Milosevic in presidential elections.

His victory, recognized after a week of anti-Milosevic protests, made him the last president of Yugoslavia.

* His opposition to the extradition of Milosevic to the Hague war crimes tribunal put him at odds with reformist Prime Minister Zoran Djindjic, who eventually signed the order in June 2001. The two men remained bitter rivals until Djindjic's death by a sniper's bullet in 2003.

* Kostunica took over as Prime Minister in March 2004, heading a patchwork minority government that was supported in parliament by Milosevic's weakened Socialist Party, a move much criticized by his former pro-Western allies.

* A vocal critic of the Hague tribunal's 'blackmail', he got over his misgivings and sent more than a dozen Serb war crimes suspects to the court to secure the start of talks on closer ties with the European Union in October 2005. The talks were frozen in May 2006 because Belgrade could not deliver top war crimes suspect Ratko Mladic.

* Since the United Nations started talks on the status of Serbia's breakaway Kosovo province in February 2006, Kostunica's focus has shifted away from reforms to the future of the territory. His increasingly hardline rhetoric against independence for Kosovo -- as backed by the West -- and his reliance on Moscow to block it, have led critics to accuse him of following in the footsteps of Milosevic.