Brussels – There is a question that inevitably arises in any discussion about EU enlargement: how many unanimous decisions are required throughout the entire accession process? Yet there is another, far less frequently asked question – one that could fundamentally change the entire debate: is unanimity actually legally necessary at every stage?
The short answer is no. A more nuanced response calls for a closer look at the different phases of the EU accession process, why unanimity has become entrenched as a legal practice over the past two decades, and how European Council President António Costa‘s recent request to the Commission and Council services might change everything. Also, how the latest threat by Orbán’s Hungary to indefinitely block Ukraine’s accession hides deeper-rooted issues: namely, the widespread reluctance among many member states to relinquish their veto power.
“After the 2004 enlargement, the appetite for admitting new members from the Western Balkans diminished,” explains Zoran Nechev, Policy and Advocacy Fellow at Think Europe, speaking to The New Union Post. “It was at that point that the requirement for unanimous approval by the Council was introduced,” enabling several countries—including Greece, Bulgaria, France, the Netherlands and Denmark – to block or delay the EU accession process for several candidates.
But everything shifted in 2022, following the outbreak of Russia’s war against Ukraine and Kyiv’s request to join the EU. Since then, the Union has appeared to rediscover its momentum for enlargement – yet without grounding it in a credible, long-term plan. As Berta López Domènech, Policy Analyst at the European Policy Centre (EPC), told The New Union Post, “we are caught somewhere between rhetoric and the absence of a real strategy.”
Compounding the problem is the obstructionism of Hungarian Prime Minister Viktor Orbán, whose veto on opening negotiation chapters threatens to derail Ukraine’s hopes entirely. Confronted with this stalemate, President Costa’s initiative aims to clarify the legal framework – what the EU Treaties do, and do not, actually require. Such clarification could help show that unanimity is not always necessary, supported by a legal opinion that might serve as “a shield in the event of political backlash” and even pave the way for “a change in methodology,” López Domènech suggests.
Is it legally possible?
“The EU member states play a crucial role in negotiating, agreeing and ratifying the Accession Treaty. That is essentially what Article 49 of the Treaty says,” explains Christophe Hillion, Professor of European Law at the University of Oslo, outlining the legal basis of the EU accession process and its voting requirements.
The Treaty-based procedure for EU enlargement envisages only one point at which the Council must decide unanimously, namely when it formally reacts to the application of a candidate country, after the Commission has given its opinion, and the Parliament its consent. In addition, the Accession Treaty must be negotiated between the member states and the candidate country, and ratified by each member state in accordance with its constitutional procedures.
By contrast, opening and closing 33 negotiation chapters by unanimous decision “is purely an institutional practice, it is not legally required” by Article 49 of the Treaty of the European Union (TEU). Yet the proliferation of unanimous decisions – around 150 for each candidate – only serves to slow the process. It is, Hillion notes, “a way of controlling, slowing down, and possibly stalling the implementation of an enlargement decision that member states have already taken upfront.”
Analysing this legal practice, the requirement for unanimity at intermediary stages – opening and closing negotiating clusters and chapters, and setting opening, interim and closing benchmarks – derives from the negotiating framework with the candidate country. This is a bilateral agreement that establishes the legal and political parameters for the accession talks that follow. For instance, Ukraine’s accession framework requires unanimity for all decisions, except when rejecting a recommendation from the Commission (which can be done by qualified majority).
This does not imply that the framework is immutable. As Think Europe’s Nechev points out, “to those who argue that the rules should not change mid-game, one can cite Montenegro and Serbia.” Their accession negotiations began under one methodology – respectively in 2012 and 2014 – but were revised in 2020 with the adoption of the cluster-based approach. In short, there is already a precedent for revising the rules during the process.
If that were the case today, Professor Hillion confirms that the issue would not end up before the European Court of Justice—with Hungary taking action against the Council or the Commission – “simply because there is no EU law that Hungary could invoke” against the other member states if they chose to continue negotiations with Ukraine.
Conversely, he suggests a different possible role for the Court: determining “whether or not Hungary is infringing its duty of sincere cooperation by vetoing the process without proper justification.” This could come into play if the other member states decided to take action against Hungary for obstructing the effective implementation of a decision the Council has already taken under Article 49. But here, we are in the realm of political will – just as with any attempt to overcome the unanimity rule.
Is there enough political will?
This is the crux of the debate over overcoming the unanimity rule at the intermediate stages of the EU accession process. “As with any practice, it can be changed. Whether there is the political will to reach an agreement remains to be seen,” Professor Hillion cautions, noting the tendency of many member states to wield their veto power to serve national – if not personal – interests.
Recent EU history shows that marginalising obstructionists is possible, sometimes through creative solutions. During the financial crisis, the question arose with Greece as to whether the Treaties needed to be amended to enable the EU to bail out a member state in distress by unanimous agreement of all member states, including those outside the Eurozone. To sidestep the United Kingdom’s obstructionism, the other EU governments acted outside the Treaty framework by adopting a complementary treaty.
If the member states were able to sideline a permanent member of the UN Security Council and one of the EU’s most influential players at that time, it should now be equally feasible to isolate the obstructionism of the Hungarian prime minister. But do they truly wish to take that step, and accept the full weight of the consequences?
“Blocking the process by one or two countries has often been used by others as cover, allowing them to hide behind unanimity while quietly supporting it,” observes EPC’s López Domènech. The narrative that Orbán alone bears full responsibility for stalling the enlargement process is, in truth, an oversimplification. Similar situations have arisen before and, if today the problem lies with Hungary over Ukraine, tomorrow it could just as easily be the turn of another member state opposing a different candidate. In short, relinquishing the veto power merely to neutralise Orbán could well backfire on other capitals in the future.
As Think Europe’s Nechev observes, “if larger member states can block progress without facing significant political costs, smaller states are likely to follow suit.” This has already happened: France, the Netherlands and Denmark blocked Albania in 2019; then Bulgaria with North Macedonia in 2020 – “and in the future it could be Croatia with Serbia, or Cyprus and Greece with Türkiye.”
It is also worth noting that Germany sought to introduce qualified majority voting (QMV) into Ukraine’s negotiating framework but failed due to opposition “from multiple member states – not just Hungary,” Nechev recalls, emphasising that “many countries are hiding behind Hungary’s more vocal opposition.” EPC’s López Domènech echoes this view: “I sense that many stakeholders are quietly hoping to stall the process, expecting that this geopolitical moment will pass without requiring actual enlargement.”
Overcoming the unanimity rule
If there were the political will to overcome the unanimity rule, viable alternatives would not be hard to find. In 2024, Germany and Slovenia submitted a non-paper (an informal document used in closed negotiations) to the Council, advocating the use of qualified majority voting for certain interim steps in the EU accession process. “With Denmark joining after taking over the presidency, around 16 member states are now supportive,” recalls Think Europe’s Nechev.
In a paper he co-authored, he argued that a “viable proposal” would be to introduce QMV into the wider EU accession process – not only for Ukraine – through “political consensus on which stages, areas or policies could be adapted.” As happened with Serbia and Montenegro in 2020, all candidate countries would be asked whether they were willing to proceed under the updated methodology. “With a single decision, it would be possible to amend all negotiation frameworks,” Nechev notes.
Professor Hillion, however, questions the need for dozens of decisions throughout the accession process. “This is, in my view, where the problem lies: the exercise of national veto rights has somehow become disconnected from the very context in which it is meant to operate,” he explains, referring to the implementation of a unanimous Council decision already taken under Article 49. Provided the candidate fulfils the required conditions, there is very little discretion for member states to oppose the continuation of negotiations, as “they are bound by obligations of cooperation to ensure the success of the process,” he stresses.
Building on Hillion’s reasoning, if a member state wishes to exercise its veto, “it must provide a justification” and demonstrate that refusing to open or close a chapter is a “proportionate” way of addressing the issue at hand. In other words, “good reasons” must be presented to persuade the other member states that the process should be halted. If they are not convinced, “then the process should continue.”
Finally, there is a more nuanced interpretation of what the EU enlargement process represents. “Can a member state’s refusal to ratify an Accession Treaty call its own membership into question?” asks Professor Hillion. At the heart of the matter lies the idea that an Accession Treaty can be regarded as a new instrument of primary law – one that defines who is, and who is not, a member of the Union. If that is the case, when an EU member fails to ratify such a treaty for reasons that bear little relevance to the accession itself, “then I don’t think the accession of a new member should be sacrificed,” he warns.
If this question were to gain prominence, “it could affect the atmosphere of the negotiations,” since what would be at stake is not only the future enlargement of the European Union but also the membership status of all those bound by the Accession Treaty – including the current member states acting as its negotiators.
Considering Orbán’s obstruction of Ukraine’s accession process – since there would be no legal grounds for him to stop the process if the other member states chose to bypass unanimity – his only option would be to withhold ratification of the Accession Treaty at the very end of the process. But then, this would raise a deeper question: “Is this simply a blockage of EU enlargement, or a decision not to remain part of the European Union, given that Hungary would be refusing to endorse the expansion of its membership?” Hillion concludes.
