The EU will agree this week to expand into a 25-member bloc stretching deep into ex-Soviet lands - but is it growing into a powerful political force, or just an unwieldy giant?
Amid much trumpeting of history-in-the-making and post-Cold War reunification, some basic questions remain.
"At the moment the EU is not at all an effective political actor internationally," said Kirsty Hughes of the Brussels-based Centre for European Policy Studies.
"The fact that it's going to be a bigger bloc is going to raise expectations about it doing more on the political side. Whether it can respond to those is much less clear. That is going to be more difficult at 25 countries."
Barring diplomatic accidents, the 15-member bloc will extend invitations to 10 mostly ex-communist countries at a summit in Copenhagen.
The event marks the climax of more than a decade of efforts since the fall of the Berlin Wall.
In its biggest expansion ever, the EU will at a stroke take in a swathe of countries whose gross domestic product per capita is a small fraction of its current leading states like France, Britain or Germany.
The geographical and social disparities alone are mind-boggling: from the city of London to the gypsy shanty towns of eastern Slovakia, from the Atlantic beaches of Biarritz to the frozen frontiers with Russia.
Not a problem, say the integrationists: only a few years ago countries like Portugal and Spain joined the club, and look at them now.
But can Latvia attract as many tourists as the Algarve, reply the skeptics.
Some analysts say that one notable winner of EU enlargement will be the United States, which will benefit from greater stability in the Old World.
The Americans, with their eye firmly fixed on Iraq, are particularly interested in the Turkey question and are lobbying hard for the country to be given an invitation in Copenhagen to start accession talks.
But Turkey remains a fundamental problem for the expanding EU. The Copenhagen summit is struggling to find a face-saving formula to meet Ankara's demands.
"The Turks are striving to develop a free and democratic and tolerant society that could be a useful model for others in the Muslim world," said U.S. Deputy Defense Secretary Paul Wolfowitz last week.
"The quid pro quo in the short run is help on Iraq and further down the line, we believe EU accession will make the Turks more flexible on Cyprus," said a senior U.S. official.
The debate over Turkey's EU prospects has been rumbling on, barely noticed for years. But it rocketed into the headlines recently when former French President Valery Giscard d'Estaing, who heads the Convention on the Future of Europe, declared that Ankara's EU entry would be the "end" of the grouping.
And there, for critics, lies the rub: skeptics say it will be virtually impossible for a 25-member club to work effectively. Any amount of qualified majority voting is not going to paper over the basic cracks.
"From Estonia in the northeast down to Portugal in the southwest, why should they have the same foreign policy interests?" said one diplomat.
The answer, for some, comes in the recent revival of the Franco-German engine. Long the driving force behind EU development, it had recently stalled. But it revved back into life at an October summit in Brussels for both sides to forge a deal on farm aid, a key stumbling block to expansion.
For others, the proposed new structures of the EU will provide the solution. Under a new constitution being worked out by Giscard d'Estaing, the EU could soon have its own president, and even be renamed the United States of Europe.
Many, though, are still asking fundamental questions about where the EU is going.
"In trade it has learned to speak with one voice, and enlargement is not going to undermine that. Enlargement is going to mean you are a bigger trade bloc, still speaking with one voice," Hughes said.
However, politically "we're not going to see huge steps forward in the EU being a real global presence, but perhaps it should start in its region," she added.