Does EU enlargement require voting reform?

EU enlargement is back on the agenda and with that, discussions of what a larger Union would look like are back as well. The EU’s expansion to 35+ member-states would pose challenges to its institutional structure and its decision-making capacities. Six countries are actively engaged in negotiations to join (Albania, Moldova, Montenegro, North Macedonia, Serbia and Ukraine); Bosnia and Herzegovina must meet a number of conditions before negotiations can start; Kosovo is a potential candidate; while the accession processes of Georgia and Türkiye remain frozen for now. While it is still unclear when and how enlargement will take place, it is clear that an influx of new members would shake up the existing institutional set-up.

An enlarged EU would face an impaired ability to make decisions quickly and efficiently. This is especially true in areas that currently require the unanimous approval of all member-states. These include the EU’s Common Foreign and Security Policy (CFSP), the budget, taxation and enlargement itself (see Table 1). Recently, the number of vetoes and threats of use of the veto has increased in these areas, foreshadowing the difficulties that a wider EU would face. Moving away from unanimity would be one way of reducing the risk of stalemate and making decision-making more efficient in a larger EU. 

This insight outlines the main challenges that a larger European Union would face and looks at whether a shift away from unanimity is necessary. It then analyses how such a shift in voting could take place, reviewing the current state of the debate. Finally, it explores what additional institutional changes would be needed to ensure a better-functioning Union. 

Shifting away from unanimity in EU decision-making: Necessary? 

The prospect of EU enlargement has reignited debates about the bloc’s decision-making procedures. While the share of decisions that require unanimity has significantly decreased since the 2009 Lisbon Treaty, in practice the Council continues to prefer consensus.

According to the EU Council Monitor, a database published by the German Institute for International and Security Affairs (SWP) that analyses the voting behaviour of national governments, the Council of Ministers voted with consensus or quasi-consensus (that is with member-states abstaining but not voting against) in more than 80 per cent of the decisions between 2010 and 2024. This is a remarkably high level, even if the percentages have decreased slightly, to below 75 per cent, in the last two years. In effect, the Council is behaving as if unanimity still applied in areas where it does not; in fact, in many cases no actual voting took place as there was agreement between all member-states. 

Consensus has also been the modus operandi for the European Council (EUCO), the heads of state and government, who set the overall political direction and priorities for the EU. While the EUCO is not a legislative body, its political guidance has been necessary on sensitive topics, such as the EU’s climate targets, for the other institutions to proceed. 

When it comes to the countries that voted against the majority in the Council, the United Kingdom (before Brexit) was outvoted most often, followed by Hungary and Poland. In environmental policy – an area that rarely requires unanimity – the Council’s reliance on consensus has been more variable. After a few years with relatively high levels of agreement, only 30 and 50 per cent of decisions were taken by consensus, in 2023 and 2024, respectively. Poland, Hungary and Bulgaria voted no or abstained most frequently. 

Two developments have made building consensus more difficult: agreement among EU members on certain topics has decreased, while the need to respond quickly to global events has grown. Russia’s full-scale war against Ukraine and the Trump administration’s repositioning of the United States – as disinterested in Europe’s security and hostile to the EU as an institution – have fundamentally changed the geopolitical context. These challenges require member-states to react quicker than ever before. 

At the same time, the number of reported vetoes, including of non-binding statements in the European Council (EUCO), has increased in recent years. A total of 45 vetoes took place between 2011 and 2025, with one-third of them reported in the last year-and-a-half. Hungary has wielded its veto most often, voting no 19 times, followed by Poland with seven vetoes. 

Some of the vetoes have reflected genuine policy disagreements, but unanimity requirements have also been hijacked by bilateral disputes and abused by member-states to extract concessions on unrelated issues. Cyprus, for example, in 2020 vetoed sanctions against Belarus to put pressure on the EU in a dispute with Turkey; and Hungary is continuously threatening to veto the extension of Russia sanctions in an attempt to unfreeze suspended EU money. In March this year, Hungary twice vetoed a joint EUCO statement on providing Ukraine with continued support, but the remaining 26 member-states ignored the veto and published the Council conclusions anyway, emphasising the EU’s (quasi) unity.

But there are limits to the degree to which one can exclude truculent member-states, both legally and in practice. The treaties, for now, require unanimity in foreign policy. And it would be difficult to appear united if more than one member-state objected – the Council, for example, managed to bring Slovakia on board for the March votes on support to Ukraine, despite its government being quite sympathetic to Russia, but it may not be able to do so in the future.

Still, eliminating unanimity has its drawbacks. If a member-state is persistently outvoted on nationally sensitive topics, it could boost anti-EU sentiment. And getting rid of unanimity would not necessarily ensure smooth decision-taking – it only provides a solution in cases where there are a small number of recalcitrant member-states. Groups that include larger member-states can still block decisions in the case of qualified majority voting (QMV), the EU’s standard voting procedure. QMV requires that 55 per cent of all member-states (currently 15 out of 27), and 65 per cent of the EU’s total population votes in favour. This means that Germany and France, the EU’s two largest countries, need the support of only a few member-states to get to 35 per cent and reach a blocking minority (which requires at least 4 countries). Their ability to block decisions would remain unchanged, even if all the Balkans countries, Ukraine and Moldova joined.

An EU of 35+ would require more, not less consultation, slowing down processes further. Institutional reform and enlargement are therefore often discussed together. In fact, member-states have sometimes instrumentalised reform to block progress on enlargement, saying that enlargement is impossible without institutional changes. This is not true – the EU did not undergo significant reform before its ‘big bang’ enlargement of 2004, when it welcomed ten new member-states. Although the need for reform was widely recognised as a precondition to improve the EU’s ‘absorption capacity’, only limited changes took place during the Amsterdam (1997) and Nice (2001) treaties, due to a lack of consensus and fears that major shifts would destabilise the delicate balance between member-states. 

An EU of 35+ would require more, not less consultation, slowing down processes further. 

Still, what is different this time is that an enlarged Union would reach a size where decision-making becomes inherently more difficult. And given that unanimity is already straining the EU’s responsiveness in foreign policy, sanctions and enlargement itself, the addition of eight to ten new members – with diverging interests in many policy areas – could risk institutional paralysis. 

In other areas, such as environmental policy, the issue is less pressing as the Council reaches most of its decisions by qualified majority. But there are a few exceptions even in those cases. According to Article 192 of the Treaty on the Functioning of the European Union (TFEU), decisions of a fiscal nature in environmental policy and those affecting certain areas such as land use and energy supply require unanimity. Even environmental policy is therefore not immune to the risk of paralysis.

Pathways to QMV

There are two ways to eliminate unanimity from EU decision-making: by changing the treaties or by using provisions that already exist within them. 

Treaty changes are particularly burdensome and lengthy processes. They require unanimous agreement among all member-states, followed by ratification in each country, involving national referendums or parliamentary approvals. These can be politically contentious and time-consuming, especially when sensitive issues like sovereignty are involved. The failed constitutional treaty of 2005, which was rejected in referendums in both France and the Netherlands, has made EU leaders wary of pursuing treaty change without adequate preparation. The rise of far-right parties, which reject further EU integration, also makes the present moment unfavourable for such an overhaul.

Precisely because treaty changes are an onerous undertaking, the EU has some legal options to bypass unanimity. The first option involves the so-called passerelle clauses, which allow the Council to shift to QMV in defined areas. There are two general and six policy-specific such clauses, including one on environmental policy. The main problem with the passerelle clauses is that their activation requires unanimity – which is why they have been used only once, in 2004, to shift voting procedures to QMV in the field of visas and border controls. Still, one way to expand QMV before enlargement would be to gradually add, or ‘phase in’, new policy areas via the use of passerelles, as suggested by the so-called Franco-German working group, a group of experts commissioned by the French and German governments to come up with ideas on institutional reform.

Precisely because treaty changes are an onerous undertaking, the EU has some legal options to bypass unanimity.

The European Parliament (EP) has agreed with this approach; in a 2023 resolution it argued that the expansion of passerelles to several policy fields, including CFSP, energy, taxation and the remaining areas of environmental policy, could be an interim solution to facilitate decision-making while treaty change takes place. The newly elected EP – even though it contains a larger number of far-right and eurosceptic forces – has continued to support moving away from unanimity. In fact, the EP and the Commission have long called for the use of passerelle clauses, with the latter specifically recommending them in energy and environmental taxation. For example, shifting to QMV could facilitate the revision of the Energy Taxation Directive (ETD), which forms part of the Green Deal. 

A majority of member-states has expressed willingness to use passerelle clauses on a case-by-case basis, but the Council is very divided on the more general principle of whether to completely eliminate unanimity. The so-called Friends of QMV group, which now includes 12 member-states, among them Germany, France and Italy, favours expanding QMV in CFSP. 

But several small- and medium-sized member-states are wary of losing influence and being dominated by large countries. For some, such as Cyprus and Greece, the prospect of losing their ability to veto common foreign policies is anathema. Others, such as Sweden or the Netherlands, say they would never give up their vetoes over tax policy. At the far end of the spectrum, Hungary is calling for QMV to be rolled back significantly and for most, if not all, decision-making powers to be allocated to national governments; a move that would strip the Commission and the EP of their current powers. Another problem for the proponents of more QMV is that not all the countries which profess to want it are sincere. For example, there are questions over whether Germany is really committed to QMV on tax, and whether France is really willing to give up its veto on foreign policy. 

To convince sceptics, the Franco-German working group recommended some ways to protect national interests in case of a shift towards more QMV. This could be done through the use of a ‘sovereignty safety net’, which would allow member-states to object if a vital national interest was threatened. But such an objection would need to clear an additional step to turn into a veto: a vote with QMV on whether to transfer the matter to the EUCO for high-level discussion. If treaty change was on the table, member-states could also secure opt-outs, choosing not to participate in a specific policy field; or agree on rebalancing QMV shares to, for example, 60 per cent of countries and 60 per cent of the population – thereby making domination by large countries less likely.  

In addition to the passerelle clauses, in CFSP member-states can resort to ‘constructive abstention’ as defined in Article 31(1) of the Treaty on the European Union (TEU). This allows countries to opt out of a unanimous vote and its implementation (but they need to respect the decision and accept that it remains binding on the EU). Constructive abstention was used in 2008, when the EU set up a security policy mission in Kosovo, and three times since Russia’s war against Ukraine started. In October 2022, Austria, Ireland and Malta abstained from supplying lethal weapons to Ukraine; while Hungary abstained in the vote establishing the Military Assistance Mission in support of Ukraine (EUMAM Ukraine) in the same month and also in May 2024, in the vote creating the Ukraine Assistance Fund (UAF). Hungarian Prime Minister Viktor Orbán’s ‘coffee break’, which allowed the EU to open accession talks with Ukraine in December 2023, was not a formal use of constructive abstention. 

In foreign policy, there is another option that could help to speed up decision-taking, which does not involve treaty change or even the use of passerelles. Article 31(2) of the TEU allows QMV to be used for the implementing details on foreign policy – so long as the Council decides, unanimously, in favour of this. The Council has used it only occasionally, amending listings under the EU’s sanctions regime, for example.

As the start of accession talks with Ukraine demonstrates, enlargement has long suffered from both abuse and the legitimate use of national vetoes. Introducing more QMV in enlargement decisions would therefore be in the interest of accession countries. A German-Slovenian proposal in 2024 recommended shifting to QMV for technical decisions during the enlargement process – but not for major political decisions such as approving accession. This approach could significantly reduce veto opportunities, making the process smoother for accession countries. And since enlargement is an inter-governmental process, such a change would not require amending the treaties.

QMV and ‘gradual integration’

To move forward on enlargement, the EU has recently turned towards the model of ‘gradual integration’, which would allow accession countries to progressively benefit from EU membership as they meet certain benchmarks. This could mean participation in particular policy areas or programmes. Gradual integration would lessen the immediate financial and political burden on current members as they could absorb new countries more slowly. Such a change could do away with the need to sequence enlargement and institutional reform – and even allow for a phasing in of QMV in an increasing number of policy areas, simultaneously with gradual integration. 

As suggested in 2023 by the think-tanks CEP Belgrade and the Centre for European Policy Studies, candidate countries could also participate in EU institutions in a more gradual way. The ‘staged accession’ model (see Chart 2) would allow candidate countries to learn the ropes and gain access to decision-making powers more gradually. When it comes to voting, the staged accession model suggested no voting rights in the early stages and no veto powers until full membership – which could address concerns about decision-making in an unreformed EU. 

Enlargement also raises the question of increased differentiation within the EU – that is, the ability to opt out, or go slower or faster than others in certain policy areas. Differentiation already exists in the EU of 27: the eurozone includes 20 countries, while the passport-free Schengen area comprises all EU members, excluding Ireland and Cyprus. The Franco-German working group recommended more flexibility in co-operation among member-states, while maintaining the integrity of EU policies. This could be done by moving towards what they describe as ‘concentric circles’ of membership (see Chart 3), with four distinct tiers: the Eurozone, the EU, associate members and the European Political Community (EPC). Such a setup would allow for more enhanced co-operation between those that are willing to go further in a certain policy area. If member-states fail to move towards full QMV, a more differentiated EU and the use of enhanced co-operation would also allow coalitions of the willing to sidestep opposition and do more together.

Beyond QMV: The areas that need reform in an enlarged EU

Enlargement raises a number of other institutional questions, besides moving away from unanimity. These include the need for a leaner European Commission, a rebalancing of representation in the European Parliament, and a reform to the rotating presidency of the Council. 

Some of these changes would help streamline decision-making and increase efficiency, while others could address smaller member-states’ fears about being dominated by big ones. The Treaty of Lisbon already called for a decrease in the size of the current Commission, where every country is represented by one commissioner, but member-states did not implement the change. Enlargement has prompted renewed calls for such restructuring. Similarly, think-tanks suggested that the rotating presidency – where member-states currently work in trios to co-ordinate the work of the EU, with each taking the helm for six months – should be revamped or entirely scrapped for the sake of efficiency. And finally, a potential increase in the size of the EP could serve as an opportunity to revisit its seat allocation – which lacks a fixed formula and is decided ahead of each election – and ensure fair representation of both new and existing member-states. This would help to maintain the EP’s democratic legitimacy.

Conclusions

While unanimity has historically helped to foster consensus, it increasingly risks leading to stalemate and delay, particularly as the EU prepares to expand to 35+ member-states. Enlargement demands broader institutional adjustments as well, including a leaner Commission and rebalanced representation within the European Parliament. Moving away from unanimity in areas such as foreign policy or sanctions would be particularly important for faster action in a radically changed geopolitical environment. When it comes to environmental and climate policies, the shift towards QMV is less urgent but can still provide benefits. 

Transitioning away from unanimity presents challenges, particularly for smaller member-states concerned about diminished influence. Existing mechanisms, such as the passerelle clauses and constructive abstention, offer potential ways forward without requiring cumbersome treaty changes. Yet they represent only partial solutions, given that the activation of passerelle clauses requires unanimity.

Ultimately, the debate surrounding unanimity versus QMV reflects broader questions about the EU’s adaptability in a rapidly changing global landscape. Domestic developments, such as the rise of the far right, including in larger and more powerful member-states, underscore the importance but also the complexity of adjusting EU decision-making. 

The debate surrounding unanimity versus QMV reflects broader questions about the EU’s adaptability in a rapidly changing global landscape.

In the long run, enlargement may need to be combined with differentiated integration, where different membership tiers would entail different benefits and distinct institutional rules. This would make decision-taking smoother. However, even in a multi-tier EU, all full members would need to take part in certain policy areas such as the single market and the CFSP, where decisions can require unanimity. This means that moving away from unanimity and towards QMV is a question that EU leaders will not be able to avoid.

Zselyke Csaky is a senior research fellow and Charles Grant is director of the Centre for European Reform.

This article has been supported by the European Climate Foundation. Responsibility for the information and views set out in this article lies with the authors. The European Climate Foundation cannot be held responsible for any use which may be made of the information contained or expressed therein.