The proposal received no more welcome in Belgrade, where parliament in December voted to reject any treaty which did not treat Kosovo as part of Serbia - including the EU deal.
That threat "is serious," said Colonel Christopher Langton, senior fellow for conflict and defence diplomacy at the Institute for International Strategic Studies in London.
Despite the dangers, however, experts say that the union still has the potential to turn the situation into a stunning success.
29 January 2008: DPA
Brussels - The European Union prides itself on having brought peace to Europe after a century of war. That claim now faces its greatest challenge as the Serbian province of Kosovo moves closer to declaring independence.
"Kosovo is clearly in the EU's back yard. The EU can't afford to let it run out of control," Professor Andrew Taylor, an expert on South-East European politics at the University of Sheffield, told Deutsche Presse-Agentur dpa.
Kosovo's population is 90 per cent Albanian, and their goal is independence. They have already fought one war with Belgrade, and have been under UN rule since 1999.
On January 24, Kosovo's Prime Minister Hashim Thaci said that he would announce a date for a declaration of independence "very soon."
Experts warn that that could trigger further conflicts, with Albanians in Serbia and Serbs in northern Kosovo and Bosnia- Herzegovina following suit.
That "is a possible scenario," said Michael Emerson, EU security policy expert at the Centre for European Policy Studies in Brussels.
They also warn that any EU move to recognize Kosovo's independence could dangerously antagonize Serbia's population.
"If the Serbs retreat into the bunker mentality of Serbdom, it will be very difficult to get them out," Taylor said.
The timing could not be more sensitive. Serbia is half-way through presidential elections, with the pro-EU incumbent lagging behind his ultra-nationalist rival, Tomislav Nikolic - a man who has in the past called for Serbia to reject the EU and turn to Russia.
And while EU leaders have wrangled over how to treat Belgrade, Nikolic's call has found quick and vocal support in Moscow.
"The Russian side sees this as a lovely chance to get a foothold in the Balkans again," Emerson said.
Indeed, in December, EU leaders agreed that they should send a civilian mission to Kosovo, to help the new state develop its public institutions and maintain the rule of law.
Russia at once threatened to veto that in the UN, leaving the legal basis for the mission in doubt.
Then the EU's biggest states said that they would recognize Kosovo's independence. But a handful, led by Cyprus, refused to consider it, saying that this would encourage separatists elsewhere.
Next, some member states, anxious to offer Serbia an olive branch, proposed offering it a speeded-up path to EU membership.
But again a minority group, this time headed by the Netherlands, rejected the idea, saying that Serbia should first cooperate fully with international war-crimes investigators.
The proposal received no more welcome in Belgrade, where parliament in December voted to reject any treaty which did not treat Kosovo as part of Serbia - including the EU deal.
That threat "is serious," said Colonel Christopher Langton, senior fellow for conflict and defence diplomacy at the Institute for International Strategic Studies in London.
Despite the dangers, however, experts say that the union still has the potential to turn the situation into a stunning success.
Serbia is not the only former Yugoslav state to be offered an EU future. Slovenia has already joined, Croatia is expected to do so soon, and Bosnia, Macedonia and Montenegro are eager to follow.
Even in Serbia, a significant segment of the population supports the idea of membership. That would be likely to grow if Serbia's neighbours began to reap the benefits of their pro-EU track.
"In 15-20 years, people (in Serbia) could come to see the status quo as unsustainable," Taylor said.
On January 28, EU foreign ministers offered Serbia a deal on free trade and travel, presenting it as a "signal to the Serbian people," while denying that it was intended to influence the vote.
If Serbia's voters were to accept that offer and opt for future EU membership, it would hand the bloc a trump card, because Serbia could only join if it regularized its relationship with Kosovo.
"One of the great advantages of the long EU accession process is that it forces potential members to get involved in their own conflict resolution," Langton said.
That scenario depends on many factors, not least Serbia's willingness to keep heading towards the EU and Russia's ability and desire to provide a realistic alternative to EU membership.
But above all, it depends on EU members' ability to swallow one harsh lesson: that even in their own back yard, their credibility and influence are only as great as their ability to unite.
Learning that lesson looks like the toughest challenge of all.
