It’s almost 11 years since Croatia became the last country to join the European Union, despite the ongoing efforts by states from the Western Balkans to accede to the Bloc. In recent years several countries in the region have found their progress stalled by bilateral disputes with their EU-member neighbours, and more keep arising. 

As more countries approach accession – Bosnia & Herzegovina, Georgia, Moldova and Ukraine have all been given candidate status since Russia’s invasion of Ukraine in 2022 – there are fears these efforts by EU members to exert pressure on their neighbours will intensify. 

In the latest development, Bulgarian President Rumen Radev hinted Sofia may use its position to exert pressure on Serbia over the Bulgarian minority in the neighbouring country. 

Radev did not explicitly threaten Serbia. However, when giving an award to Ivan Nikolov, a prominent member of the Bulgarian minority in Serbia, he mentioned “the challenges faced by our compatriots” in Serbia and said Sofia is working on a “consolidated, clear national Bulgarian position and policy in support of all our compatriots abroad”. 

“The president indicated that he will continue to work actively with the Serbian state leadership to solve the problems of the Bulgarians in Serbia,” said a statement from the presidency. 

"Bulgaria is the main engine of the European integration of the countries of the Western Balkans, and the main criterion by which we will give support is the situation of our compatriots in each country – the conditions for their economic and social development, and above all the opportunity for them to defend their national identity, language, culture, historical memory,” he added. 

This is not the first time the Bulgarian issue in Serbia has become a political issue. In December 2023, a cross-party group of Bulgarian MEPs complained of what they called a “hate campaign” against the Bulgarian minority in Serbia, which number about 13,000 people. 

Radev’s comments were noteworthy as Bulgaria has already exerted significant pressure over another EU accession candidate, North Macedonia. Sofia refused to back the go-ahead of accession talks with Skopje until the Macedonian side agreed to include its small Bulgarian minority in the country’s constitution. 

The centre-left government in power in Skopje until recently struggled unsuccessfully to get the constitutional changes through the parliament in order to get started on its accession talks; its failure was one of the reasons for its ousting in the recent general and presidential elections.

Bulgaria made its demands after Greece, another neighbour, had held back North Macedonia from starting accession talks for years. Athens objected to the country name, at that time “Macedonia”. Only after politicians in Skopje agreed to change the name to “North Macedonia” did Athens lift its objections. 

The new stalling of accession progress for North Macedonia – a candidate country since 2005 – also held back Albania, which has been coupled in the process, prompting the country’s Prime Minister Edi Rama to complain Tirana had been “held hostage” by disputes between third countries. 

Meanwhile, there are already signs the new government and president in Skopje will be less accommodating to the country’s neighbours, with uncertain consequences for the EU accession process. 

Newly elected President Gordana Siljanovska-Davkova backed by the right-wing VMRO-DPMNE sparked a crisis in relations with Greece when she pointedly used her country’s old name – Macedonia instead of North Macedonia – during her swearing-in ceremony in May. 

Siljanovska-Davkova’s decision to avoid using the constitutional name North Macedonia could potentially lead to new tensions with Greece and Bulgaria.

Not only is Albania held back by North Macedonia’s dispute with Bulgaria, it has more recently become embroiled in a dispute with Greece over the arrest and later conviction of Fredi Beleri, an ethnic Greek Albanian and the elected mayor of the city of Himara. 

Beleri was elected mayor of Himara despite being arrested ahead of the May 14, 2023 local elections on accusations of vote buying. In March 2024, he was sentenced to two years in prison. 

This threatens to derail Albania’s accession process. Greek officials have warned for months that Albania – a candidate country since 2014 – risks jeopardising its EU accession progress if Beleri is not released. However, Albanian politicians, including Rama, insist that justice must take its course through the court system.

The impact historic grievances are having on the accession processes of countries in the Western Balkans may be replicated elsewhere. 

Croatia's entry into the European Union came after resolving political conflicts with Slovenia. The border dispute between these two nations marked the first occasion where the EU officially mediated to facilitate the enlargement process. Differences occasionally flare up, for example over Pirin Bay. 

Then in 2016, in its turn Croatia postponed the opening of two chapters for Serbia, setting out specific demands mostly linked to the legacy of the war of the 1990s.

As more countries from the region join, more disputes are likely to flare up, unless Brussels makes some plan to deal with these. 

Serbia and Kosovo, both aspiring EU members, are already required to normalise their relations if either is to progress towards membership in the bloc. 

Yet this is only the most serious of many potential conflicts in a region with a history of recent war and ethnic strife. 

Outside the Western Balkans, there are already indications that Ukraine may face similar struggles connected to ethnic minorities living on its territory. 

Hungary has taken an obstructive position on Ukraine’s progress towards EU accession, and not only because its leader Prime Minister Victor Orban is the friendliest of all EU leaders towards Russian President Vladimir Putin. 

Budapest insists on addressing its concerns about the rights of national minorities in Ukraine ahead of an expected decision on whether to give the go-ahead to the first intergovernmental conferences with Ukraine and Moldova at the EU General Affairs Council on June 25.

Orban has frequently claimed that Ukraine's government is violating the language rights of approximately 75,000 ethnic Hungarians living in Zakarpattia, particularly in education and public administration. As a result, his administration has obstructed essential European Union funding for Ukraine and has threatened to hinder the country's progress toward EU membership.

Romania, another neighbour of Ukraine’s, also has a minority in Ukraine, while the two states have historically contested areas along their shared border, notably Snake Island. Despite this, Romania has consistently supported Ukraine against Russia's invasion as well as advocating for EU accession for both Moldova (its closest international ally) and Ukraine. 

Amid the hike in enthusiasm for accession after Russia’s invasion of Ukraine, resident Charles Michel said in August 2023 that the EU and the Western Balkans should be fully prepared for enlargement by 2030. The response from the region was sceptical, and with good reason. Michel made the comment shortly after the 20th anniversary of when EU leaders gathered in the Greek port city of Thessaloniki and promised the Western Balkans a future in the bloc.

It was only after years of stagnation that enlargement suddenly moved up the political agenda within the EU since Russia’s invasion of Ukraine starkly demonstrated the importance of European unity in the face of external security threats. Not only did the EU speedily offer candidate status to Ukraine and Moldova – something other countries such as Albania waited years to achieve – it also took the long-awaited step of greenlighting accession negotiations with Albania and North Macedonia. 

Now, proponents of enlargement, which are concentrated in Central and Southeast Europe, have been exploring options to make the process smoother and less vulnerable to holdups connected to bilateral disputes. 

Among these, Slovenia and Germany presented an initiative at the EU's General Affairs Council in January, aiming to enhance the efficiency of decision-making in the EU enlargement process. The proposal suggests a shift from the current consensus-based approach to a qualified majority voting system for decisions on opening new chapters in accession talks.

“One way to keep enlargement on track could be for the EU to separate bilateral disputes – whether between member states and candidate countries or between candidates themselves – from the accession process and work towards their resolution on a parallel track,” said a recent paper by Tefta Kelmendi, deputy director, Wider Europe at the European Council on Foreign Relations (ECFR). 

“The potential for disputes to hinder progress will ultimately remain, but this separation could help redress the balance between the political aspects of enlargement and candidates’ progress on reforms and alignment with EU laws and standards.”

There is also a clear connection between holding back the process because of bilateral disputes and waning enthusiasm for enlargement in the region. 

This is already very apparent in Serbia, where just 40% of the population support EU accession, according to one recent poll. Another poll, carried out in summer 2023, showed that given the choice between joining the BRICS bloc of major emerging markets or the EU, 46.9% of respondents would pick BRICS, compared to just 35% the EU. In North Macedonia there is also widespread disillusionment with the EU accession process following the country’s repeated setbacks.