For the first time since Brexit, the European Union has a credible chance to grow again. Montenegro and Albania are nearing the finish line, Ukraine and Moldova are taking their first decisive steps away from Moscow's orbit, and Iceland is weighing a return to accession talks. But as the bloc's enlargement ambition becomes concrete, Brussels faces a moment of truth: how to absorb a larger, more complex Union without breaking its own machinery.
The current momentum is unprecedented in years. EU officials point out that more negotiating chapters have been closed in the last six months than in the previous decade. Enlargement has increasingly been used as a foreign policy tool—to consolidate influence in the neighbourhood, extend security guarantees, and anchor stability in a volatile geopolitical landscape. Yet the prospect of an expanded Union forces a reckoning with a series of political and strategic questions that have long been deferred.
Geographical balance and the Serbian question
The 2004 "Big Bang" enlargement, which brought ten central and eastern European states into the fold, left many western capitals feeling that the bloc's centre of gravity had shifted too far east. The current frontrunners, Montenegro and Albania, are too small to alter that balance, but their progress raises a trickier issue: how to handle Serbia, the Western Balkans' most significant country and a divisive topic among member states.
The so-called "Friends of the Western Balkans" have questioned whether Belgrade's accession bid is being judged on merit alone. They warn that the process is not applied equally across candidates. As pressure builds to open more accession clusters with Ukraine and Moldova before year-end, calls for geographical balance are growing louder. Some fear that Ukraine's progress could become tied to Serbia's, creating an unwelcome linkage.
Iceland could offer an unexpected counterweight. The wealthy Nordic country is holding a referendum, with voting open until 29 August, on whether to resume its EU accession talks. A yes vote would rebalance the bloc's economic make-up and add a voice that is both Nordic and Atlanticist.
Ukraine, however, is the elephant in the room. EU capitals are acutely aware that some form of European membership or security guarantee will have to feature in any eventual peace deal with Moscow. Despite its modest economy, Ukraine's territory, population, and military capacity would make it an influential member state, particularly on defence and foreign policy. That prospect forces Brussels to confront how an expanded Union would actually function.
Reform or paralysis
In her 2023 State of the Union address, European Commission President Ursula von der Leyen announced pre-enlargement policy reviews—a blueprint for how an EU of 30 or more member states would work. The plan was quietly shelved for years, as Ukraine's bid complicated the question both practically and politically. The Commission is now due to publish it on 30 September, as the executive seeks to reclaim the initiative.
European governments have been debating how to manage the next wave of candidates. Ideas range from stronger democratic safeguards for new members—a legacy of Hungary's experience under Viktor Orbán—to gradual integration that delivers early, tangible benefits. More fundamentally, the Commission is expected to propose reforms to the EU's own inner workings to ensure it can continue to function once enlarged.
Calls to end the unanimity requirement on foreign policy have grown louder, part of a broader push to make the bloc's external action more decisive. Orbán's repeated use of the veto has left a deep impression. Another idea is to make the European Commission leaner by scrapping the principle that each member state gets one commissioner—a move that smaller countries resist.
Sceptics argue the timing is wrong for such deep reform, with several key EU countries facing elections next year. France is a case in point: the prospect of a far-right, Eurosceptic National Rally candidate winning the presidency has never felt more real. Others counter that there is always an important election somewhere in Europe, and that long-delayed reforms cannot wait.
Ratification uncertainty
The enlargement process has always assumed that member states are willing to accept new members. Typically, grievances are aired before accession negotiations are complete—North Macedonia's long-running disputes with Greece over its name and with Bulgaria over minority rights are notable examples. But blocking accession outright at ratification stage would be unprecedented, though it remains a real risk. The political spectrum has shifted rightward in founding members like the Netherlands and France, making voters generally warier of enlargement.
Montenegro's head of mission to the EU, Petar Marković, told Euronews that one of the main reasons his country is willing to accept additional safeguards on rule of law and democratic backsliding is precisely to smooth the ratification process. France is the biggest question mark. In 2005, Paris introduced a constitutional amendment requiring any new accession treaty to be put to a national referendum, or approved by a three-fifths majority in a joint session of parliament.
The coming months will test whether the EU can match its rhetorical ambition with the political will to reform. The bloc's ability to absorb new members without diluting its own effectiveness is no longer a theoretical exercise. As the Icelandic referendum unfolds and the Commission's blueprint lands, the moment of truth is approaching.
