Which way for EU enlargement? Brussels faces moment of truth over bloc's expansion

For the first time since Brexit, the EU has a tangible chance to grow again. But as countries like Montenegro fast approach membership while others look to Europe as a security anchor, Brussels' enlargement ambition is about to face its moment of truth.

The EU's enlargement is riding a once-in-a-generation momentum, with several "frontrunners" nearing the finish line, Ukraine and Moldova taking their first definitive steps out of Moscow's orbit, and Iceland weighing whether to resume accession talks.

The situation has not looked this promising in years, with EU officials boasting that more negotiating chapters have closed in the last six months than in the past decade.

Brussels has increasingly wielded EU accession as a foreign policy tool — to consolidate its influence in its immediate neighbourhood, extend security guarantees that curb the influence of hostile powers, and anchor stability amid a volatile geopolitical landscape.

But as the prospect of an expanded Union becomes more concrete, EU institutions and member states are being increasingly confronted with a series of political and strategic questions that will come to a head if the next wave of enlargement happens.

Geographical balance

A key factor the Union's expansion must account for is geographical balance, especially given the 2004 "Big Bang" enlargement. Back in 2004, 10 new central and eastern European states joined, leaving many western European capitals feeling the EU's centre of gravity had shifted too far east.

The current frontrunners, Montenegro and Albania, would not alter that balance given their modest size. Still, as they near the finish line, they pose a trickier question of how to handle the Western Balkans' most significant country, Serbia, which remains a divisive topic among member states.

The so-called "Friends of the Western Balkans" have been questioning the geopolitical considerations shaping Belgrade's accession bid. They warn that the merits-based process is not being applied equally across candidate countries.

As pressure builds to open more accession clusters with Ukraine and Moldova before year-end, calls to maintain geographical balance are only bound to grow louder and could result in Ukraine's accession progress becoming dependent on Serbia's.

Iceland could be an unexpected and welcome factor in rebalancing the bloc's economic make-up: the wealthy Nordic country is holding a referendum, with voting open until 29 August, on whether to resume its accession talks with the EU.

Ukraine, meanwhile, is the elephant in the room. EU capitals are well 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, Kyiv's territory, population and military capacity would make it an influential member state, particularly on defence and foreign policy — forcing Brussels into a broader reckoning over how an expanded Union would actually function.

Need for reform

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 then 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 EU executive looks to reclaim the initiative.

As enlargement has shifted to the top of Brussels' agenda, European governments have been debating how to manage the next wave of candidate countries. They have floated ideas from stronger democratic safeguards for new members, a legacy of Hungary's experience under Viktor Orbán, to gradual integration designed to deliver early, tangible benefits of EU membership.

More fundamentally, the Commission is expected to propose reforms to the EU's own inner workings to ensure Brussels can continue to function once enlarged.

Calls to end the unanimity requirement on matters like foreign policy, for instance, have grown louder. It's part of a broader push to make the bloc's external action more decisive in a tense geopolitical climate — another legacy of Orbán repeatedly holding EU decision-making hostage.

The idea to make the European Commission leaner and more agile in refocusing on emerging priorities could resurface again. This would involve scrapping the principle that each member state gets one commissioner, which is backed by smaller countries.

Sceptics argue the timing is wrong for such deep reform, with several key EU countries facing elections next year. One such country is France, where the prospect of a far-right, Eurosceptic National Rally candidate winning the presidency has never felt more real.

Others counter that there's always an important election somewhere in Europe, and that long-delayed reforms cannot wait.

Ratification uncertainty

The EU enlargement process has always assumed that member states are willing to accept new members into the club.

Typically, EU countries air their grievances before accession negotiations are complete. North Macedonia's long-running disputes, first with Greece over its name and later with Bulgaria over minority rights, are among the most notable examples.

But while blocking accession outright at ratification stage would be unprecedented, 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.

As Montenegro's head of mission to the EU, Petar Marković, told Euronews, 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.

Once again, Montenegro is set to be the test case. Its ratification could end up bundled with Albania's, however, depending on the pace of Tirana's progress, or with Iceland's, depending on the referendum outcome.

"If Montenegro can't make it, then of course that derails the process in a very serious way," Florian Bieber, coordinator of the Balkans in Europe Policy Advisory Group, told Euronews. "There needs to be a very clear contingency plan to deal with this scenario."

Reporting from euronews contributed to this story.