British Prime Minister David Cameron, in a long-awaited speech on the European Union, has promised British voters the choice of whether to quit the EU -- if his party wins the next general election. Cameron said his government will offer an "in-or-out" referendum after it renegotiates the terms of its relationship with the bloc.
RFE/RL's Brussels correspondent Rikard Jozwiak looks at how a possible "Brexit" -- or even a looser relationship between Britain and the EU -- might affect the bloc's enlargement and foreign policy.
What would EU's foreign policy look like without Britain?
Most likely a bit more insular and much less global. Britain is the top military spender in the EU and has the biggest diplomatic corps among the member states. Stefan Lehne of Carnegie Europe points out that the EU would lose out in almost every aspect.
"The departure would be a huge loss for the European Union," Lehne says. "I think we would be weaker in just about every sense of the word. In a military sense, in the diplomatic sense, in terms of our economic power in the world. So it could be quite a tragic loss for the European Union."
How would the EU's enlargement policy in the Western Balkans be affected?
Britain sees EU enlargement as a way to stabilize the neighborhood and expand the EU single market already awash with British products.
Jana Kobzova of the European Council of Foreign Relations (ECFR) notes that although Britain hasn't always been a driving force in the Western Balkans, it has been an important ally.
"It is one thing when Slovakia is arguing for the Western Balkans, for a specific country there to be part of the EU," Kobzova says. "And it is quite another [issue] when Britain says the same thing."
There is, therefore, a big risk that after Croatia joins in July that the EU enlargement door will be all but shut for years to come. True, Germany pays lip-service to the idea of the countries in the Western Balkans joining the club. But it has so far been too preoccupied with economic crisis management to put pressure on Greece into solving a long-running naming dispute blocking Macedonian entry or to cajole the five EU member states that don't recognize Kosovo to do so.
What about the countries in the EU's Eastern Neighborhood?
If the EU keeps its official commitment to bring in the former Yugoslav republics, the door would be firmly boarded up for EU neighbors to the east.
Rosa Balfour from the Brussels-based European Policy Centre (EPC) says that countries such as Georgia, Moldova, and Ukraine would lose an important voice in Brussels.
"These countries want a prospect for [EU] accession and Paris and Berlin are not willing to grant that prospect of accession," Balfour says. "Without Britain, you have lost a heavyweight, shall we say, in favor of having an open-door policy. I would say the prospects are pretty bleak."
Would the EU be friendlier toward Russia if Britain wasn't at the table?
Possibly. France and Germany, but also other big EU countries such as Spain and Italy, are happy to strike deals with Russia on energy issues without asking too many questions. Without Britain, the other camp of countries that usually prods Moscow on thornier issues would lose a champion, says Kobzova.
"Britain was among the countries that put emphasis not only on the sort of material benefits of the cooperation with Russia but was also looking into the kind of human rights and democracy side of things," she says, "arguing that the problems that Russia has when it comes to corruption, lack of governance, and so on should be of concern to the European Union, which some other countries had not [argued]."
Could a possible "Brexit" have any positive effects on the EU's foreign policy?
There is a distant chance that the EU might become a more coherent foreign policy actor and achieve what many Euro-federalists have dreamt of: a single EU representation at international bodies such as the UN Security Council. Balfour points out that there is a provision in the EU's legal framework that entered into force in late 2009.
"The Lisbon Treaty itself foresaw that the EU would search for a single representation in international organizations," Balfour says. "This has not happened because of the obstructionism of the British position since the entry into force of the Lisbon Treaty. And in many cases that has been to the detriment of the EU's standing in various international organizations. This would probably change if Britain were to leave."