The narrow victory of Boris Tadic in the Serbian presidential elections has been greeted with relief in the European Union, in Washington, and on the Belgrade stock exchange. The vote amounted to a virtual referendum on Mr Tadic’s pro-EU policy, as opposed to the defensively nationalist and pro-Russian policy of his challenger, Tomislav Nikolic. Although most Serbs are bitterly opposed to the prospect of independence for the breakaway province of Kosovo, a majority still voted for the long-term perspective of joining the EU.

Mr Tadic’s re-election means that Brussels can now go ahead with a political agreement with Belgrade this week. It does not amount to signing a full-scale Stability and Association Agreement, but it will allow negotiations to start on benefits such as visa facilitation for Serbs visiting the EU. It is a signal of good intent.

Although the nightmare scenario of a hardline nationalist victory may have been avoided, the way forward for Serbia, Kosovo and the EU is still fraught with danger. Kosovo is determined to declare independence within a matter of weeks, and Serbia – including Mr Tadic – will refuse to recognise it. But the US, and most EU member states, will do so, accepting the inevitable. Russia will block any UN resolution, so Kosovo’s sovereignty will be very limited.

In Belgrade, the fragile coalition between Mr Tadic’s Democratic party and the prime minister Vojislav Kostunica may well fall apart. Mr Kostunica wants a hardline response to Kosovo’s independence, including diplomatic sanctions against the west. He mistrusts Mr Tadic’s attempt to separate the question of Kosovo from the longer- term aim of EU membership. So he refused to back the president in the election campaign, to the understandable fury of the Democrats.

The Serbs are their own worst enemies. They have refused to recognise the unstoppable process of Kosovo’s independence, following the failed ethnic cleansing launched by Slobodan Milosevic against Kosovar Albanians in 1998. But Mr Tadic’s victory is what Brussels wanted. The EU should recognise how far Belgrade has come since the days of Milosevic. The stability and association agreement, blocked by the Netherlands because of Serbia’s failure to arrest Ratko Mladic to face war crimes charges in the Hague, should be swiftly signed.

Mr Mladic must be arrested before Serbia can ever hope to join the EU. Kosovo will also have to be recognised. That will take time. Brussels must help to buy it.