Bilateral vetoes: Slovenia’s blockage of Croatia’s EU accession negotiations

From late 2008 to October 2009 Slovenia blocked Croatia’s EU accession negotiations over a bilateral border dispute. While an agreement signed by the prime ministers of the two countries on 4 November 2009 has resolved the problem, for those interested in the future of EU enlargement in South Eastern Europe a number of pressing questions remain. Why and how did this conflict escalate? What was its real cost to Croatia’s accession process? What made an agreement possible?

The dispute also raises more general questions. What should be the EU’s policy in future instances of such bilateral disputes and vetoes? How can the EU address the fact that virtually all Yugoslav successor states still have unresolved border issues with at least some of their neighbours (including Croatia, which has them with Bosnia-Herzegovina, Montenegro and Serbia)? How to ensure that future disputes do not escalate? And does this case hold any lessons for dealing with other vetoes, such as those currently affecting Macedonia’s (by Greece) and Turkey’s (by Cyprus and France) accession process? Can this crisis be turned into an opportunity for the EU in the Balkans?

These questions will be addressed in a forthcoming ESI report. In the meantime, listen to ESI’s Kristof Bender for an 11 minute summary of the background to the dispute:

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  • For information on Slovenia’s EU accession and Croatia’s EU accession process visit ESI’s country sections on Croatia and Slovenia (see in particular Slovenia’s road to the EU).
  • Portrait of Dimitrij Rupel, Slovenia’s long-time foreign minister
  • Portrait of Alojz Peterle, Slovenia’s prime minister during Italy’s blocking of Slovenia’s EU accession process in the mid-1990s.


Further reading:

  • Arbitration agreement between the Government of the Republic of Slovenia and the Government of the Republic of Croatia, 4 November 2009.

Academic articles

Slovenian documents

Croatian documents

UN Documents

International media coverage

“Slovenian Foreign Minister Samuel Zbogar on Friday (19 December 2008) said in Ljubljana the EU was ‘obviously not paying enough attention to the interests of member states, which it should be representing, but [was] looking to reach results in the area of enlargement’.”

  • To view the conflict through the eyes of Josko Joras, whose house lies in an area controlled by Croatia, but who refuses to acknowledge Croatian authority, click here.
  • For more on Josko Joras’ house, see this article in

“Every time this guy has a conflict with the Croatian police, it’s a lead item on the television news.”

“It’s easily missed on a map, but this small bay of just 20 square km (eight square miles) is making big diplomatic waves.”

“With tensions on both sides rising … no solution was found.”

“Talks between Croatia and Slovenia about European Commission proposals for mediation in a border dispute broke down yesterday (18 June), hours before a summit of European Union leaders.”

  • Swedish Foreign Minister Carl Bildt called for a period of reflection just before his country took over the rotating EU presidency on 1 July 2009. Watch him here.

“This is a bilateral dispute. Responsibility for solving bilateral disputes rests with the countries themselves. They should not impede the accession negotiations in our opinion, but they have done so as we know.”

“‘The European Commission has tried to help Croatia and Slovenia solve their 18-year-old dispute. But, after six months of work and discussion, I believe it is up to Croatia and Slovenia to find a solution,’ Mr Rehn said.”

“It seems like such a small dispute … and yet it is undermining the stability of this region.”

“‘This is not only a historic day for Croatia, Slovenia and the EU, but for the entire international community,’ said Slovenian Prime Minister Pahor. ‘Today we have shown that we solve problems, we do not create them’.”

18 February 2010