Why does the enlargement of the EU to the Western Balkans keep getting stuck?
When the member states promised the countries of the Western Balkans a European perspective at the summit in Thessaloniki in 2003, many believed that the integration of the region would be a matter of a few years. More than two decades later, the record is sobering: in the region so far only Croatia, which joined in 2013, is a full member of the Union. The remaining countries are at different stages of the process, with some of them waiting at the gates of the Union for almost two decades already.
The accession process itself follows a strict logic of conditionality: the candidate must adopt the entire body of law of the Union, which is divided into 35 negotiating chapters, from public procurement to environmental protection. Each chapter is opened and closed only after previously defined benchmarks have been met, and for each of these steps the unanimous consent of all member states is required. Precisely this unanimity rule, which was meant to protect the interests of every member, in practice gives every government the opportunity to take the entire process hostage in its bilateral disputes.
Montenegro, which has been negotiating since 2012 and has opened almost all chapters, is considered the most advanced candidate. In the case of Serbia, with which negotiations began in 2014, progress is considerably slower, among other things because Brussels links its European future to the normalisation of relations with Kosovo. Albania and North Macedonia, for their part, officially opened negotiations only in 2022, after years of waiting in the waiting room of the Union.
The Macedonian case shows particularly clearly how strongly bilateral issues can shape the process. Although the country received candidate status as early as 2005, Greece blocked the start of negotiations for years, because it believed that the name Macedonia implied territorial claims on its northern region of the same name. The dispute was only overcome with the Prespa Agreement of 2018, under which the country accepted the name North Macedonia, which for many citizens was a painful compromise. Instead of the expected breakthrough, a new blockade followed: Bulgaria demanded the inclusion of Bulgarians in the Constitution as a minority, as well as concessions on questions of history and language. Since a two-thirds majority in parliament is required for a constitutional amendment, this demand deepened political divisions, and part of the public saw it as an intrusion into national identity.
Beyond bilateral disputes, the key criterion remains the rule of law, which Brussels has placed at the very centre of the accession methodology in recent years. According to this logic, the chapters on the judiciary and fundamental rights are opened first and closed last, so that progress in all other areas depends on them. In the reports of the Commission political influence on the judiciary, a selective fight against corruption and pressure on independent media are regularly criticised. Critics also warn that the formal adoption of laws means little if they are not consistently implemented in practice.
However, responsibility does not lie with the candidates alone. In several member states enlargement is unpopular, and governments fear that the admission of new, relatively poor states would overburden the budget and the institutions of the Union. That is why the voices are growing louder that the Union must, before the admission of new members, reform its own procedures, for example by abolishing unanimity in foreign policy. Others, on the other hand, warn that any further delay would open space for Russia, China and other external actors, which are already trying to increase their influence in the region. The Russian invasion of Ukraine in 2022 did give enlargement new political momentum, but so far that momentum has only partly translated into concrete progress for the Western Balkans. Whether the countries of the region will become members in the next decade will be determined above all by one thing: the willingness of both sides to keep their own promises.