FUTURE OF EUROPEAN UNION: SCENARIOS FOR REFORM, ENLARGEMENT AND DEFENSE INTEGRATION

Marianna Fakhurdinova, Yehor Tkachuk, Maksym Molotai

Experts at the Transatlantic Dialogue Center

Key Findings

• The European Parliament and the European Commission encourage a shift to qualified majority voting (QMV) in the Council of the EU, but there is no consensus among the member states.
• A shift to QMV through amendment of the EU founding treaties is a lengthy and unlikely path. In the Common Foreign and Security Policy the alternatives are the mechanism of constructive abstention, under which a dissenting state does not block a decision, and the passerelle clauses of the Lisbon Treaty, which allow a move to QMV with the support of all member states; in enlargement, the alternative is amendment of the negotiating framework with a candidate country.
• Ukraine has experienced the weaponization of the enlargement process first-hand: Hungary blocked the opening of negotiating clusters with Ukraine for more than a year, despite the positive assessments of the European Commission. A shift to qualified majority voting, at least at the intermediate stages, would already significantly reduce the politicization of the enlargement process.
• A shift to QMV in the Common Foreign and Security Policy would allow the EU to adopt sanctions packages against the Russian Federation over its war against Ukraine more quickly and, in the longer term, to increase sanctions pressure on the aggressor state.
• The “multi-speed Europe” model allows a group of EU states to deepen integration in particular areas through the enhanced cooperation mechanism, with decisions legally binding only on the participants. A number of states are already deepening cooperation through the “E6” format in competitiveness and security.
• The “multi-speed Europe” model could accelerate Ukraine’s integration into the EU defense architecture, in particular through closer engagement with the “E6”, since Kyiv is ahead of many member states in terms of defense capabilities.
• In enlargement, the models under consideration for candidate countries are fast-track accession, reverse enlargement, gradual accession and associate membership. None of them enjoys sustained support, but work on them continues.
• Although all the models offer certain advantages for Ukraine at the intermediate stages, they carry the risk of reducing member states’ interest in further enlargement and of entrenching Ukraine’s status as a “second-class” member.
• EU member states continue to rely on NATO for security. Although Article 42(7) of the Treaty on European Union is legally stronger than Article 5 of the Washington Treaty, it has no clear mechanism of application. Creating a joint army is unlikely because of the absence in the EU of a single political center, a leading state, command structures and sufficient capabilities.
• France’s updated nuclear doctrine provides for deeper cooperation with six European states, joint exercises and the possible deployment of Rafale aircraft on their territory. Paris, however, will retain sovereignty over its nuclear forces, will not take on binding commitments to defend its partners and will not replace the American nuclear umbrella.

1. EU Reform: Possible Shift to Qualified Majority Voting in Enlargement and Security

The question of internal EU reform returned to the Union’s agenda after 2022. The abuse of the veto by individual member states slowed the adoption of strategic decisions and exposed the EU’s vulnerability in situations that require a rapid response – from the war in Ukraine to the change in US foreign policy. At the same time, granting Ukraine candidate status reset the enlargement process and brought back the prospect of an EU of more than 35 member states, in which reaching unanimity will be even harder.

Today around 80% of decisions in the EU are taken by qualified majority voting (QMV). Under the Lisbon Treaty, such a decision must be supported by at least 55% of member states representing 65% of the EU population.

Unanimity in the Council of the EU is retained in the most sensitive areas: the Common Foreign and Security Policy (CFSP), enlargement and finance.

To avoid blockages, the EU has already used both existing and ad hoc mechanisms. In 2022, through the “constructive abstention” mechanism, Austria, Ireland and Malta did not take part in financing arms supplies to Ukraine, while Hungary stayed out of the creation of the European Union Military Assistance Mission in support of Ukraine and, later, of the Ukraine Assistance Fund.

Under Article 31(1) of the Treaty on European Union, a state that has abstained from a vote in foreign and security policy is not obliged to implement the decision, but must accept that it commits the Union and refrain from obstructing its implementation. A procedure similar in substance was applied in 2023 during the decision to open accession negotiations with Ukraine: Hungary’s Prime Minister Viktor Orbán left the room and effectively abstained.

To overcome Hungary’s “vetocracy”, the EU also tried to suspend its voting rights under Article 7 of the Treaty on European Union. However, despite systematic violations of EU principles and interests by Viktor Orbán’s government, the procedure produced no result because of the lack of unanimity.

Introducing QMV Through Amendment of EU Founding Treaties

Such piecemeal solutions, however, do not address the problem systemically. In the long run the drivers of EU institutional reform, primarily Germany, seek a full transition of the Council of the EU to QMV across all areas before the next enlargement. This requires amendment of the Union’s founding treaties – the Treaty on European Union (TEU) and the Treaty on the Functioning of the European Union (TFEU).

This could be done through Article 48 TEU, which provides for convening a European Convention, unanimous agreement of the member states and subsequent ratification by their national parliaments. The process can take years and does not guarantee a result.

In September 2023, an independent working group presented recommendations on reforming the EU. It proposed several ways to speed up treaty change..

To ease the concerns of skeptics, the group proposed safeguards for the move to QMV. In particular, a “sovereignty safety net” would allow any state to suspend the adoption of a decision if it threatened its vital interests. Another option is to change the QMV formula from 55% of states and 65% of the population to 60% and 60%.

Nevertheless, there is generally no appetite among member states for treaty change. The veto allows them to advance national interests. Positions also differ by area: for Sweden and the Netherlands it is important to keep the veto in tax policy, and for Cyprus and Greece in foreign policy.

Introducing QMV Without Amendment of EU Founding Treaties

The most realistic approach for now is therefore a short-term one: the gradual introduction of QMV in individual areas without amending the founding treaties. The most relevant areas for Ukraine are EU enlargement and the EU’s Common Foreign and Security Policy.

·       QMV in CFSP

Apart from “constructive abstention”, the main route to QMV in the CFSP without treaty change is the passerelle clauses – the transitional provisions of the Lisbon Treaty that allow the Council of the EU to move from unanimity to QMV in a given area. Member states must, however, support such a decision unanimously. In addition, in some countries this step requires ratification by their parliaments.

The transition is supported by the “Group of Friends” on QMV in EU foreign and security policy, created by France and Germany in 2023. Their position rests on the EU’s need to respond to crises faster without being blocked by individual countries, as Cyprus did over EU sanctions against Belarus in 2020, or Hungary over sanctions against Russia in 2022–2024, pressing for the unfreezing of European funds for itself.

At the same time, most states are cautious about QMV in the Common Foreign and Security Policy, since these areas bear directly on sovereignty and, for the neutral Austria, Ireland, Malta and Cyprus, also on the foundations of their security and defense policy. Smaller states also fear that giving up the veto would reduce their weight and strengthen the influence of the large countries. The demographic criterion of QMV, in particular, favors Germany and France, whose combined population accounts for around a third of the EU’s.

Nevertheless, the move to QMV in the CFSP through the transitional provisions comes with safeguards and limits. Article 31(2) contains a safety net mechanism that allows a member state to block a decision taken by QMV for “vital and stated reasons of national policy”. Article 31(4), meanwhile, does not permit QMV to be applied to decisions with defence or military implications.

●      QMV in Enlargement

If QMV in the CFSP is needed for faster decisions that are critical to the Union’s ability to act, QMV in enlargement is meant to adapt the institutions to a larger membership without the EU losing its capacity to function. It is also meant to limit the blocking of the technical accession process because of bilateral historical or territorial disputes, which undermines candidates’ trust in the EU.

The history of EU enlargement illustrates this problem well. Greece and Bulgaria opposed North Macedonia and Albania for more than 10 years; and Hungary has opposed Ukraine over the question of national minorities and its wish to secure the unfreezing of EU funds.

The EU enlargement methodology updated in 2020 narrowed the room for manipulation in part: grouping the 35 chapters into 6 clusters reduced the number of opportunities to block progress. Any intermediate step, however – approving the negotiating framework, for example, or assessing the criteria for opening clusters – still requires the unanimity of all member states.

This unanimity is an established practice, however, rather than a treaty requirement.

A move to QMV in enlargement policy therefore does not require amendment of the founding treaties or use of the passerelle clauses, which do not apply to enlargement. It can instead be effected through a procedurally simpler mechanism – revision of the negotiating framework with Ukraine and/or other candidates in the part concerning negotiating procedures. The decision on such a move would nevertheless still require the unanimous agreement of all member states.

In view of this, the most realistic option is a compromise scenario: applying QMV to the intermediate or technical stages of the negotiations while retaining consensus on accession itself and on ratification of the accession treaty. These are the models currently under discussion in the EU:

• Full QMV: applying a qualified majority at all intermediate stages of the negotiations, including the opening and closing of clusters and chapters, with unanimity retained only for the decision on the membership application, the terms of accession and ratification of the accession treaty.
• “Consensus-like” QMV: applying QMV to all intermediate stages of the negotiations, but under the formula of 72% of member states in favor, with no requirement as to the share of the population.
• “Dutch” QMV: applying a supermajority (72% of member states representing at least 65% of the Union’s population) to all intermediate stages of the negotiations except the closing of all chapters linked to the “Fundamentals” cluster, while the key decisions on the membership application, the terms of accession and ratification of the accession treaty are taken unanimously.
• German–Slovenian proposal of 2024: QMV applies only to the opening of negotiating clusters and the approval of initial benchmarks, while decisions on the membership application, the terms of accession, ratification of the accession treaty and the closing of chapters remain unanimous.

Some researchers warn that a move to QMV at the intermediate stages of accession could lead to the Accession Treaty being blocked at the end if member states and candidates fail to settle bilateral issues in good time.

All the proposals considered remain at the level of discussion.

The ambiguous positions of member states and the coming electoral cycles, in particular the strengthening of right-wing parties in France and Germany, may nevertheless narrow the space for reform again. In the near term, therefore, the most realistic path is a gradual, sectoral move to QMV without amendment of the founding treaties in the areas where unanimity does the most damage to the EU’s ability to act and to enlargement.

2. Prospects for Multi-Speed Europe Model

In contrast to the German idea of federalizing the EU and moving fully to qualified majority voting, the French model of a “multi-speed Europe” assumes different rates and depths of integration of states into the EU and into particular formats.

The concept has been discussed in the EU since the 1980s. The idea of a multi-tier EU gained new impetus in 2023 after the report of the Franco-German working group. The document proposed closer integration of the most ambitious states and identified four levels of participation:

• An inner circle of members of the euro area and the Schengen area, as well as “coalitions of the willing” in climate, energy, taxation and other policies;
• All current and future EU member states;
• Associate members, involved primarily in the single market but without voting rights in the Council of the EU;
• Participating countries of the European Political Community.

In 2026 the concept took practical shape, in connection with the need to provide Ukraine with a loan of 90 billion euros. The decision was supported by 24 member states, without the participation of Hungary, Slovakia and the Czech Republic. To avoid their veto, the countries used the enhanced cooperation mechanism provided for by Article 20 of the Treaty on European Union.

The mechanism allows at least nine states to deepen cooperation in particular areas and to adopt legally binding decisions.

At the same time, member states fear that excessive differentiation will weaken EU unity and turn the Union into an “exclusive club”. In practice, the “multi-speed Europe” model is most clearly visible in EU competitiveness, security and enlargement.

Competitiveness

At the beginning of 2026, Ursula von der Leyen called on member states to make more active use of the enhanced cooperation mechanism amid pressure from the United States and China. In the same period the finance ministers of Germany and France launched the E6 format, which brought together the six largest EU economies, which together account for around 70% of the Union’s population and GDP.

The format aims to strengthen EU defense, create a Savings and Investments Union, reinforce the euro and secure critical raw materials.

The first result of the E6 was agreement among the participants on reforming financial markets.

Security

The E6 also aims to accelerate the growth of defense spending and the implementation of industrial policy. The group’s countries host the EU’s most competitive defense companies.

At the same time, states are not always able to agree even on joint defense programs. In June 2026, France and Germany decided to end joint development of the Future Combat Air System (FCAS) fighter and of next-generation tanks.

Differences also exist over which spending in the next EU budget should be cut. At the same time, progress on joint procurement, security integration and coordinated investment could turn the format into a model of cooperation for states that are willing and able.

Enlargement

Differentiated integration also became topical in the context of EU enlargement in the spring and summer of 2026, primarily because of a potential 2027 deadline for Ukraine’s accession. The following models were considered:

• Fast-track accession – reducing bureaucratic procedures in order to sign the Accession Treaty within a short time frame.
• Reverse enlargement – formal accession to the EU without rights. The main funds and voting rights in the Council of the EU would remain blocked until the candidate completed its reforms.
• Gradual accession – the candidate’s step-by-step involvement in individual policies and in the single market in exchange for reforms, but without formal membership.
• Associate membership – symbolic representation in the European Commission and Parliament and military guarantees under Article 42(7) of the Treaty on European Union, but without voting rights, access to funding or the status of a full member.

The member states effectively rejected the first three models. The idea of associate membership drew criticism in Ukraine as a possible form of “second-class” membership.

For now, the EU and Ukraine continue along the path of merit-based accession, which is meant to prevent both the political “deception” of candidates. The process is held back by delays in opening negotiating clusters and by Ukraine’s uneven progress on reforms.

3. Security of Europe: Prospects for Creating Joint EU Armed Forces

Europe remains highly vulnerable to security threats, as the United States is increasingly focused on deterring China. Washington’s intention to shift most of the responsibility for NATO’s conventional defense capabilities onto European allies as early as 2027 does not match the pace of Europe’s rearmament.

Despite the differences within the Alliance, Europeans continue to rely on it for defense while trying to close the specific capability gaps created by the reduced role of the United States. In response to the reduction of the American presence, the German-Netherlands army corps will take over command of NATO land forces in Estonia and Latvia.

A separate issue remains the security of EU members that are not in NATO. These are Austria, Cyprus, Ireland and Malta. This problem is also relevant in the context of Ukraine’s accession: membership in the EU is regarded by Kyiv as a “soft guarantee” of security.

The Treaty on European Union already contains a collective security mechanism. Article 42(7) obliges all EU members to provide a state that has suffered aggression with “aid and assistance by all the means in their power” – wording that is stronger than in NATO’s Article 5 (“such action as it deems necessary”). Likewise, the threshold for applying the EU’s Article 42(7) is lower (“armed aggression”), than in NATO’s Article 5 (“armed attack”).

Although applying Article 42(7) does not require a decision of the Council of the EU, the sequence of actions by member states and EU institutions remains extremely unclear. To address this problem, in May 2026 the EU held an exercise intended to work out a clear algorithm of actions in the event of a threat to a state that is an EU member but not a NATO member, and to establish what role the EU institutions should play in such a crisis. The results of the exercise remain non-public. Either way, the EU’s Article 42(7) is complementary to NATO’s Article 5 and will not replace it any time soon.

Current EU initiatives aim to improve the existing security architecture rather than to create an alternative to it. Permanent Structured Cooperation (PESCO) is aimed at strengthening cooperation between participants in the military industry. The EU Rapid Deployment Capacity is limited in size (5,000 troops), so it is not sufficient to defend Europe. Because of this, voices are again being heard today about the need to create joint European armed forces.

The main argument of those who support this idea is that a single army would be more effective than the 27 separate armies of EU member states and would not depend on US unpredictability. Such an alliance would in any case be difficult to realize, because the European Union currently lacks a political center ready to bear responsibility for EU security, an integrated military command and significant rapid reaction forces as an.

First of all, the European Union does not have the capacity to create and deploy a large army. To replace the American land presence on the eastern border, Europe needs a force of 100,000 troops. Mobilizing that number will be extremely difficult, however, given the reluctance of populations in many EU countries to join the army and the need to keep part of their forces combat-ready under commitments within NATO.

In addition, the EU has almost no experience of taking part in full-scale combat operations: its 23 missions and operations under the CFSP mandate are extremely limited in scale.

The European Union also has no command structures that would ensure successful management of joint forces. The EU’s military strategic headquarters is designed for only 60 permanent staff – hundreds of times fewer than NATO’s equivalent personnel. The unwillingness to duplicate NATO’s command structures is one of the main obstacles to creating a European army.

Finally, unlike NATO, where leadership belonged to the United States, no European state is ready to take responsibility for the security of the entire European Union. Placing such responsibility on the European Council, where any state could veto the deployment of troops, would be ineffective.

The creation of joint EU armed forces therefore remains a distant prospect. European states are searching for alternative formats to ensure their own security, but none of them is aimed at replacing NATO’s role. At the strategic level, Europe’s defense remains institutionally in the same format as it was before the arrival of the second Trump administration, and only an existential threat to the EU could change that.

4. Question of “Europeanization” of Force de frappe

President Macron’s March speech on the Europeanization of French nuclear forces provoked a vigorous reaction from partners. To assess the scale of the change, however, it is worth recalling the constant elements of French doctrine. At its origins stood President de Gaulle, who sought independence from alliances.

Historically, the doctrine concerned exclusively French vital interests and the territory of France. French nuclear doctrine, however, defines neither “vital interests” nor the perimeter of weapons use precisely, and ambiguity is its central element.

Specific scenarios for the use of nuclear weapons are not set out, but French analysts point to extreme cases: the threat of occupation or strikes against the political leadership. Limited attacks, including drone strikes, are not grounds for a nuclear response.

As a state with a small nuclear capability, France is compelled to rely on strategic ambiguity. Its arsenal is designed to make it possible to inflict irreparable damage on an enemy and deter it from attacking. The French nuclear forces have two components: the sea-based one and the air-based one, represented by Rafale strategic aviation.

French nuclear deterrence has thus traditionally been sovereign and has deliberately preserved strategic ambiguity. Its “Europeanization” therefore does not mean turning French weapons into a common European guarantee.

Macron’s idea is not new. In 1992, François Mitterrand first announced the possibility of creating a European nuclear doctrine; and Macron himself invited partners to a dialogue back in 2020.

Now, however, these statements have provoked keen interest because of the transformation of the European security architecture: Russia’s full-scale war against Ukraine, the reorientation of the United States toward domestic security and the Indo-Pacific region. Europe has again faced existential risks, and nuclear weapons have returned to the center of the debate.

In this context, Macron’s 2026 speech is not a departure from the previous doctrine but rather its adaptation to new threats. The president suggested that France’s vital interests may encompass a broader context, including the security of allies. There is no clear definition of these interests, however.

To implement this approach, Macron outlined a strategy of forward deterrence – closer cooperation with a limited number of European partners. This means regular consultations, the possibility for allies to take part in nuclear exercises and the potential deployment of Rafale aircraft on partners’ territory (forward deployment). For the first time since 1992, France will stop reducing and will begin building up its nuclear forces, while the number of warheads will be classified.

These changes have clear limits, however – they broaden the political horizon of French deterrence but do not change its institutional architecture. France retains full sovereignty: the decision to use its nuclear forces is taken by the French president alone. There is no question of sharing powers with partners, joint nuclear planning or the transfer of French nuclear forces to allies.

This creates a certain asymmetry: partners can take part in consultations, exercises and the potential deployment of French capabilities, but do not influence the decision on their use. This approach differs from the American doctrine, under which countries can agree or refuse to allow the use of nuclear weapons from their territory.

In addition, since the new doctrine does not clearly define vital interests, it contains no binding guarantees of protection for allies or of the use of nuclear forces if they are attacked. Closer cooperation may give rise to inflated expectations that Paris may not meet: “partners may begin to believe that they have a place at a table where in reality there is only one chair”. Unpredictability, which strengthens deterrence of an adversary, thus at the same time complicates interaction with partners.

The initiative is also limited by the narrow circle of states involved. Macron outlined a group of only eight countries with which France will deepen cooperation. The partners do not include the Baltic states, Finland or Norway, which border Russia and are under direct threat.

In the absence of joint command structures, the new doctrine deepens France’s bilateral cooperation with partners, turning it into a multi-bilateral framework. The United Kingdom and France have long cooperated in the nuclear sphere under the Lancaster House Treaty (2010) and the Northwood Declaration (2025). The central role among the new partners will be played by Germany: in March, President Macron and Chancellor Merz announced the creation of a Franco-German nuclear steering group. Merz also announced the participation of German forces in French nuclear exercises in 2026.

The French initiative is not, however, an alternative to American deterrence. French nuclear forces remain complementary to the American ones and are not intended to replace the American nuclear umbrella. Paris is preparing rather for scenarios in which US involvement could be delayed or run into political obstacles.

Tellingly, the United States has responded to the initiative with restraint. Support for the French initiative from Germany, Belgium and the Netherlands, where American nuclear warheads are deployed, indicates that dialogue with France does not contradict their commitments within the Alliance.

The logic of complementarity also explains France’s reluctance to join NATO’s Nuclear Planning Group (NPG). France did not become a member even after returning to NATO’s command structures in 2009, which had symbolic significance for preserving nuclear independence. Participation in the NPG remains a domestically sensitive subject, since it could be interpreted as a “transfer” of the nuclear role to the EU or to Germany.

In France, Macron’s speech was received favorably overall across different parties, since he preserved the Gaullist independence of sole decision-making and ambiguity. Building up the forces without publishing the number of warheads simultaneously reduces domestic resistance, sends a signal to enemies.

At the same time, support for Macron’s speech does not guarantee the durability of the new nuclear policy. After the 2027 elections, a new French president may declare a different doctrine. In addition, the return of nuclear weapons to the center of the debate may reduce the population’s readiness for a conventional clash if citizens see them as a sufficient security guarantee.

Changes to French nuclear doctrine thus have above all a communication effect. Greater ambiguity about the scope of nuclear weapons use, a possible increase in the number of warheads and a potential widening of the geography of their deployment are meant to make French deterrence less predictable for enemies. This approach also requires the fewest resources, since it demands no additional defense spending, is acceptable to different political forces in France, preserves its sovereignty over its nuclear forces and gives partners no binding guarantees. At the same time, French nuclear doctrine creates more uncertainty for partners, entrenching two contradictory imperatives: Europeanness and sovereignty.

The publication is prepared under the project “Strengthening the Analytical Capabilities of the Foreign Policy Decision-Making with the Civil Society” of the Centre for International Security with the support of the Konrad-Adenauer-Stiftung Ukraine.

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