Spain on January 1 becomes the first country to hold the EU's six-month rotating presidency under the new Lisbon Treaty, which dramatically alters some of the bloc's foreign policy-making mechanisms.
Madrid will be in a position to establish important precedents for the way the member states work together with the EU's new full-time presidential and foreign minister posts.
But the EU is also about to find out whether its foreign-policy focus has become more stable -- and whether Spain's traditional preoccupation with its southern neighbors will overshadow cooperation with the countries of the Eastern Partnership.
Before the Lisbon Treaty, the EU's regional foreign policy could be subject to enormous shifts in focus, as different countries with vastly different priorities would assume the bloc's six-month rotating presidency, and with it, temporary control of the foreign-policy agenda.
Until now, the rise of a country like Spain to the bloc's rotating presidency would have virtually guaranteed the EU's attention would swing south to the countries of North Africa, in preference over projects further east.
Under the Lisbon Treaty, this should no longer be the case -- theoretically, at least. In practice, the EU is entering in uncharted waters as it attempts to forge a new foreign-policy path using both old mechanisms, like the rotating presidencies and the foreign affairs council of ministers, and new ones, like the posts of a single foreign-policy chief and EU president.
Nowhere have early signs of Spain's intentions been more anxiously awaited than in Ukraine, Belarus, Moldova, Armenia, Azerbaijan, and Georgia -- the six post-Soviet countries that make up the EU's Eastern Partnership program.
Speaking in Brussels earlier this month, the Spanish secretary of state for EU affairs, Diego Lopez Garrido, sought to assure the Eastern Partnership countries that they would be a "priority."
"As [a representative of] the incoming presidency, I would like to say that the European Neighborhood Policy, and specifically the Eastern Partnership, will be one of the priorities of the agenda -- not only of the next trio of presidencies, comprising Spain, Belgium, and Hungary, but also concretely, of the coming Spanish term," Lopez Garrido said.Maghreb Preference
The pledge struck some as a surprise. Over the past decades, Spain has emerged, alongside France, as a dedicated promoter of closer EU engagement with the Maghreb countries facing it across the Mediterranean Sea -- Morocco, Algeria, Tunisia, Libya, and Mauritania.
The bloc manages its relations with its Mediterranean neighbors through the Barcelona Process, which is meant to guide the North African neighbors toward greater alignment with EU laws and norms.
The process has not been a roaring success, as the authoritarian-leaning regimes of the Maghreb countries see little value in closer political cooperation with the EU. They are, however, interested in EU funds.
Between 2007-2013, the EU's southern neighbors are slated to receive two-thirds of the funding from the bloc's neighborhood policy budget -- thanks in part to Spain's influence.
This time around, however, the Spanish presidency will not necessarily tip the entire foreign-policy agenda in the Maghreb region's favor.
Under the Lisbon Treaty, member states holding the presidency will now coordinate their agendas in groups of three successive presidencies, in a bid to lend greater cohesion and long-term planning to the EU's agenda-setting.
Piotr Kaczynski of the Brussels-based Center for European Policy Studies said that while Madrid cannot be expected to abandon its commitment to the Mediterranean region, it is unlikely to bar cooperation with the bloc's eastern neighbors.
"Of course, during the Spanish presidency, the Eastern Partnership will not be high on the agenda of the rotating presidency. But the Spaniards have already said they will not be blocking the development of the Eastern Partnership," Kaczynski said.
According to Kaczynski, even if Spain can't be expected to go out of its way to promote the interests of the EU's eastern neighbors, it is likely to respond positively to initiatives emanating from the EU's executive European Commission, eastern member states, and eastern neighbors.
This should mean that nothing will prevent the six neighbors' progress in negotiating and signing association agreements with the EU during the next six months.
But the fate of the eastern neighborhood hangs on more than Spain. Much will depend on the two new posts created under the Lisbon Treaty: the president of the EU Council, Belgium's Herman van Rompuy, and the new high representative for foreign affairs, Britain's Catherine Ashton.
Van Rompuy will relieve Spain of the task of chairing EU summits, while Ashton will chair EU foreign ministers' meetings. But neither is a natural leader, and their selection reflects the preference among many EU states for low-profile figures to hold the top jobs.
As a result, it is possible that by stripping the rotating presidency of agenda-setting powers in the field of foreign policy, the Lisbon Treaty will have inadvertently created a vacuum at the very heart of the EU.
If so, it's a vacuum that Spain would likely be eager to fill. Prime Minister Jose Luis Zapatero has already told the Spanish press he does not intend to play "second fiddle" to the new president.
While EU summits in Brussels are van Rompuy's responsibility, Madrid is expected to run the show at the roughly 10 summits EU leaders will have with non-EU countries, among them the United States and Russia.
And Miguel Angel Moratinos, the Spanish foreign minister, is likely to continue the pre-Lisbon tradition of chairing the twice-yearly informal meeting of EU foreign ministers. The so-called Gymnich meetings, with their laid-back atmosphere, are instrumental in determining strategic EU responses to the most important issues on the bloc's foreign-policy agenda.