Background

Ursula von der Leyen described the European Commission she led during her first term as president (2019‑2024) as a 'geopolitical Commission', aiming to advance enlargement and stabilise the EU's neighbourhood. There was a recognised need to give momentum to enlargement, restore the credibility of the prospect of EU membership for the Western Balkans and push against competing influences from third countries, in particular Russia (e.g. information operations, political and economic influence) and China (e.g. investments and economic presence). Against this background, the Commission introduced a revised enlargement methodology in 2020. Based on four principles: credibility, predictability, dynamism and stronger political steering, it introduced thematic clusters-based negotiations to speed up the process.

Russia's full‑scale war of aggression against Ukraine that began in 2022 made enlargement policy even more important strategically. Having had already extensive political and economic relations with the EU through bilateral association agreements but fuelled by security concerns, Ukraine, Moldova and Georgia immediately requested to join the EU, with the former two currently negotiating. The Commission recognised this as a historic moment in bilateral relations, grounded in legitimate aspirations of the countries to join the Union.

Image source: Publications Office of the European Union; graphic by Gyorgyi Macsai, EPRS.

Currently, the enlargement process and accession negotiations face a range of challenges. They relate to the EU's decision‑making, e.g. the 'proliferation of decision points' requiring unanimity, and bilateral issues between Member States and candidate countries. Challenges are also tied to concerns about the costs of enlargement and the risk of post‑accession backsliding. Moreover, there are requirements for internal EU reforms to ensure that an enlarged Union functions, but no consensus on what these reforms should entail.

At the EU level, the enlargement methodology has also come under scrutiny, with calls for adaptation. The calmer political and security context underpinning the 2020 methodological reform is seen as ill‑suited to the post-2022 geopolitical environment. Stagnation in the enlargement process is considered to have created a vacuum that can be readily exploited by Russia and China through interference and other forms of influence (e.g. hybrid threats, election interference, foreign information manipulation and interference operations, projects that create economic dependencies, and security cooperation). This creates external geopolitical pressure for the EU to act more rapidly and decisively on enlargement. While remaining a merit‑based process, enlargement is regarded as 'a strategic investment in Europe's security and stability', with failure to pursue it carrying greater risks and costs for Europe.

European Commission proposals

The revised enlargement methodology of 2020 also envisaged that sufficient progress on reform priorities agreed during negotiations should lead to closer integration, as well as 'accelerated integration and "phasing‑in" to individual EU policies, the EU market and EU programmes'. This became an official framework for enlargement policy and was subsequently endorsed in the June 2022 European Council conclusions, which invited the EU institutions 'to further advance the gradual integration between the European Union and the region already during the enlargement process itself in a reversible and merit‑based manner'.

The Commission's 2025 enlargement report specified that 'accelerated, or gradual, integration seeks to bring some of the benefits of future EU accession into the pre‑accession stage by allowing a candidate country to integrate into specific areas of EU policy, notably parts of the EU single market, once legislative alignment and the capacity to implement the EU acquis [in the given area] is in place'. This approach is intended to incentivise early implementation of the EU acquis and make the transition to full membership smoother.

In 2025, the Commission initiated discussions about a modified enlargement process to better support Ukraine and overcome the enlargement deadlock. One notable proposal was dubbed 'reverse enlargement' or phased integration, and envisaged partial accession. Candidate countries would formally join the EU with limited rights and obligations and observer‑like functions. They would subsequently complete the required reforms (e.g. in the areas of anti‑corruption and the rule of law), fully adopt the EU acquis and acquire full membership rights. This format would have prioritised Ukraine and possibly be extended to other candidate countries.

An alternative option was to maintain the status quo, leaving the enlargement policy unchanged, with frontrunners Montenegro and Albania potentially joining before the end of 2029.

Another pathway entailed the deepening of 'gradual integration' by allowing candidate countries to participate in more EU programmes before formal accession. This option was taken forward by the Commission in its communication entitled 'Preparing for a wider Union' (see the Section on 'Accession negotiations: Latest developments').

The Commission has also laid out general principles guiding its approach to enlargement reform. Marta Kos, the European Commissioner for Enlargement, has stressed that no shortcuts on reforms would be allowed, and that strong safeguards against backsliding should be embedded in future accession treaties without creating a two‑tier membership system for countries that have aligned with the EU acquis. The importance of EU reforms to accommodate more than 30 Member States has also been emphasised. At the structured dialogue with the European Parliament in April 2026, Commissioner Kos reiterated and expanded these principles and the central role of fundamentals, highlighting direct benefits for citizens and businesses under gradual integration.

Member States' positions

Member States have rejected the idea of 'reverse enlargement', citing demanding accession requirements, including their own domestic legal requirements, and concerns that new members could backslide democratically and obstruct the EU agenda. Legal challenges might also concern the legality, under the Treaties, of limited or partial membership (see the Section on 'Do the EU Treaties allow special or partial membership?').

Candidate countries are also required to meet the Copenhagen criteria, which complement the accession conditions and EU values set out in Articles 49 and 2 of the Treaty on European Union (TEU) respectively. These criteria are reflected in the negotiating frameworks and remain central to Member States' positions.

Finally, the reservations of some Member States could complicate the ratification of accession treaties, one of the final steps in the accession process, since Article 49 requires ratification by all Member States and the applicant country in accordance with their respective constitutional requirements.

Additionally, Germany has voiced objections to Ukraine's target accession date of 2027, while Austria, Sweden and France have reportedly emphasised the primacy of conditionality over speed.

In response to Commissioner Kos' request to Member States to participate in reforming the enlargement process, several proposals have emerged. Germany's and France's proposals for Ukraine centre on pre‑accession benefits and status. The German model of 'associate membership' envisages substantial representation in EU institutions. Ukraine would participate in meetings of the European Council and the Council of the EU and would have associate members of the Commission and the European Parliament with no voting rights, as well as an Associate Judge (an Assistant Rapporteur) at the European Court of Justice. The proposal includes progressive application of the EU acquis and step‑by‑step access to EU programmes under direct management (but not to the entire EU budget). To prevent backsliding, it proposes a snap‑back mechanism or, alternatively, a sunset clause. It also envisages an important security guarantee for Ukraine: a political commitment by the Member States to apply Article 42(7) TEU to Ukraine.

This proposed status differs from the status of associated country, which, in the case of Ukraine, stems from its association agreement with the EU signed in 2014, which contains more limited political provisions and provisions on cooperation, and establishes a Deep and Comprehensive Free Trade Area.

The French proposal for an 'integrated state status' would accelerate Ukraine's accession, though it would exclude it from receiving funding under the common agricultural policy (CAP) and cohesion policy until full membership is granted. These statuses, conferred through a political declaration, would carry strong symbolic value, extend the EU's mutual assistance clause to Ukraine, heighten the visibility of progress and offer greater access to other funding programmes, as advancements in reforms and negotiations advance.

In preparation for the EU‑Western Balkans Summit and the EU‑Moldova Summit in June 2026, France and Germany co-developed a non-paper entitled 'A New Momentum for Enlargement' covering the Western Balkans and Moldova. The proposal centres on streamlining a merit‑ and incentives‑based accession process focused more on reforms than procedure and is linked to a pre‑accession strategy rooted in gradual integration. Progress in the accession process would give candidate countries access to benefits that could serve as 'building blocks' linking them to the EU, including participation in more joint meetings with EU institutions and opportunities to take on observer roles.

The proposal also envisages enhanced security cooperation in the context of the permanent structured cooperation framework (PESCO) and Frontex, alongside extensive participation in EU programmes and areas of the single market (e.g. energy, the emissions trading system, and policies on industrial strategy, digitalisation or critical raw materials), inspired by the European economic area model. This integration would be reversible and tailored to each candidate country, with full EU membership remaining the ultimate goal.

Similarly, Austria, Czechia, Italy, Slovakia and Slovenia have proposed a 'systematic sectoral integration' model for the Western Balkans. Based on enhanced gradual integration, it envisages merit‑based, progressive access to EU programmes and sectors (e.g. transport, energy, the digital single market and policies regarding critical raw materials), as the candidate countries close negotiating chapters.

Another proposal, entitled 'Towards a catalogue of options for future accession treaties' and put forward by the Netherlands, France, Germany, Belgium and Luxembourg, focuses on accession treaties as instruments for introducing temporary and transitional measures and safeguard clauses. The transitional measures would limit voting rights on budgetary, security and foreign policy issues, for instance. The safeguard clauses would be activated in response to backsliding on the rule of law, democratic principles or freedom of the press. This proposal also envisages giving greater prominence to the EU's principle of sincere cooperation (Article 4(3) TEU) in the future accession treaties. An analysis of the proposal casts doubt on its effectiveness, arguing that it may be too constricting to incentivise accession, while overlooking misconduct by existing Member States and the necessity for internal EU reform to support enlargement.

Overall, these proposals address two main elements: stronger gradual integration linked more closely to the accession process, and safeguard measures enshrined in accession treaties or obligations applying during a transitional period.

Do the EU Treaties allow special or partial membership?

Leaving aside proposals for gradual integration building on associated status, it remains uncertain whether the Treaties allow arrangements amounting to limited or partial membership. Article 49 TEU allows any European state that meets its eligibility requirements to apply for EU membership without further specification. The conditions for accession are laid down in an accession treaty, which in principle entails acceptance of the EU acquis and the rights and obligations arising from EU membership.

Moreover, it could be argued that the institutional architecture of the EU established by the TEU presupposes that all Member States enjoy equal membership rights and equal representation in EU institutions. Article 4(2) TEU establishes that the EU shall respect the equality of Member States before the Treaties. The institutional architecture reflects this principle: the European Council comprises Heads of State or Government of Member States (Article 15 TEU); the college of Commissioners, unless the European Council decides otherwise, comprises members from each Member State (Article 17(5) TEU); and the Council comprises representatives of Member States at ministerial level who cast their vote on behalf of their state. Furthermore, the TEU does not provide for different voting rights for Member States. Voting majorities in the Council presuppose either the majority of Council's component members (simple majority under Article 238(1) of the Treaty on the Functioning of the European Union (TFEU)) or at least 55 % of Council members representing at least 65 % of the EU's population (the standard qualified majority under Article 16(3) and (4)). In both configurations, the provisions presuppose that each Member State participates in the Council's decision‑making unless the Treaties provide otherwise.

Special rules apply in situations where a Member State decides not to participate in a Union initiative, in which case Article 238(3) TFEU applies the percentages for qualified majority voting (QMV) (at least 55 % of Council members representing 65 % of the population of these states) only to the participating Member States. This particular regime does not create opt‑outs but applies with respect to transitional provisions on non‑participation laid down in the Protocols, e.g. the non‑participation of Ireland and Denmark in measures in the area of freedom, security and justice under Protocols 21 and 22 respectively.

The qualified majority regime linked to a Member State's participation in a Union initiative under Article 238(3) TFEU also applies to enhanced cooperation. In such cases, the relevant percentages are calculated solely on the basis of the participating Member States, pursuant to Article 330 TFEU.

Although Parliament is composed of representatives of the EU's citizens (Article 14(2) TEU), the distribution of seats is determined by a decision proposed by Parliament and adopted by the European Council, allocating between six and 96 seats to each Member State. The allocation of parliamentary seats therefore presupposes that the state concerned is a Member State. However, observer status may be awarded under Parliament's Rules of Procedure (Rule 13) to representatives of an acceding country – that is, one that has signed an accession treaty but is not yet formally a member of the EU – pending ratification of the treaty by that country and all Member States as required by Article 49 TEU.

From a policy perspective, enlargement can allow a certain degree of flexibility or differentiation. Permanent territorial derogations or special arrangements have been introduced in past enlargements, for example for the Isle of Man and the Channel Islands upon the UK's accession, or through a special carve‑out of fisheries policies in the case of the Canary Islands and Ceuta upon Spain's accession. Other cases reflect the special connection of specific territories with the mainland. In the majority of cases, these special regimes were requested by the acceding state.

In other cases, the acceding state requested and obtained flexibility in specific areas. For example, in the area of free movement of capital, Malta was allowed to maintain restrictions on the purchase of secondary residence (Protocol 6 to the Act of Accession). These derogations were motivated either by the special relationship between the territories concerned and the acceding country, or by the specificity of the issue at stake. It is doubtful, or in any case subject to debate, whether a permanent carve‑out could be envisaged at the time of accession that would affect a whole flagship policy, e.g. one of the four fundamental freedoms in its entirety (free movement of goods, services, capital or workers).

On the other hand, transitional arrangements negotiated upon accession and limiting the exercise of one or more fundamental freedoms are not unknown in the enlargement history of the EU. They are, however, of an exceptional character and must be limited in time and scope. As described in detail, those transitional arrangements may consist of transitional periods, derogations or even accidental derogations. They all serve different purposes.

Transitional periods are introduced to address existing Member States' concerns about the potential impact of the accession of a new Member State. They consist in the non‑application of specific legislation or policies to the new Member State for a set period. Derogations apply only after accession has taken place and permit the temporary non‑application of certain rules to address a shock or emergency arising from or connected with the accession of a new Member State.

Accidental derogations are those not negotiated but de facto applied, in some enlargements, due to accidental events. This was the case, for example, when the translation of the EU acquis into the language of the acceding country was not ready and hence not published, a circumstance that de facto delayed the application and enforceability of the EU acquis.

The various enlargements have had different peculiarities with respect to transitional periods concerning the four fundamental freedoms. As has been noted, in the first three enlargements (1973, 1981 and 1986) the free movement of goods was not immediate, but subject to the gradual elimination of customs duties and to step‑by‑step liberalisation, while this was not necessary in subsequent enlargements as the acceding countries were already members of a liberalised economic area (the EEA) where free trade was already a reality.

In the 2004 enlargement, as well as in the 'Mediterranean' enlargements (Greece in 1981, Spain and Portugal in 1986) a serious concern was the free movement of workers. Hence, for example, a seven‑year transitional period was provided for with respect to the free movement of workers, and in the case of Greece also for inbound movements. In the 2004 enlargement, transitional periods were also widely used to restrict temporarily the free movement of workers from the eight central and eastern European countries joining the EU, while the other two new members, Cyprus and Malta, were exempt. However, a more flexible scheme was introduced than the seven‑year periods provided for at the outset in the Mediterranean enlargements.

In the 2004 enlargement, the transitional period allowed the 15 existing Member States to limit, under certain conditions, access to their labour markets initially for two years, with an extension upon notification of up to three years, while a further extension of two years was still possible in the case of particular disturbances in their labour markets. This system (also known as the 2+3+2 system) did not apply to Cyprus and Malta.

The Schengen Agreement (1985) establishing a gradual process for the removal of checks on persons at the internal borders of the EU, is a further example of differentiated or flexible enlargement. Although accession to the Schengen area also occurred gradually for countries that were already Member States at the time of the conclusion of the Schengen Agreement (e.g. Italy), or at the time of the incorporation of the Schengen acquis into the EU with the Amsterdam Treaty (1999, e.g. Greece), a specific transitional provision regulated the matter for the countries joining in the 2004 enlargement. Article 3(2) of the Act of Accession delayed their entry into the Schengen area, which took place in 2007, with the exception of Cyprus.

A similar mechanism was used for the enlargement of 2007, based on Article 4(2) of the Act of Accession, with Bulgaria and Romania entering the Schengen area in March 2024 (air and sea borders) and January 2025 (land borders). Croatia, which joined the EU in 2013, entered the Schengen area in 2023 under a similar provision (Article 4(2) of its Act of Accession).

Accession negotiations: Latest developments

While negotiations with Montenegro continue, work on drafting an accession treaty has already started. For Albania, all clusters have been opened and negotiations continue.

For Ukraine, the Hungarian government lifted its veto on the formal opening of cluster negotiations. The blockage had also affected Moldova, whose accession process was coupled with Ukraine's. The lifting of the veto enabled Member States to agree unanimously to formally open the first cluster of negotiations, on fundamentals, with Ukraine and Moldova in June 2026, the sixth cluster, on external relations, in July 2026, as well as the second cluster on internal market and the third cluster on competitiveness and inclusive growth in October 2026. Previously, the Commission and the Danish Presidency of the Council had been front-loading the process, driving reforms and monitoring their implementation at the technical level, with clusters informally opened for the two candidate countries in March 2026 to allow technical work to progress.

With interim benchmarks set for Ukraine and Moldova to meet, the EU maintains that progress on 'fundamentals' (i.e. reforms concerning the rule of law, fundamental rights, democratic institutions, public administration and economic criteria) will determine the overall pace of negotiations. The conclusions of the June 2026 European Council meeting reaffirmed the merit‑based approach to the opening of the remaining negotiating clusters.

On internal EU reform, which is distinct from the accession methodology but is addressed alongside it as they both affect the EU's readiness for enlargement, a few issues stand out. In its 2024 communication on pre-enlargement reforms and policy reviews, the Commission had already stressed that the EU would have to deal with the challenge of 'further complexity of decision‑making processes and the need to maintain undisputed respect for and continued application of the EU's core values'. This built on the call from EU Heads of State or Government for intra‑EU preparedness for enlargement, made in the 2023 Granada Declaration.

The Commission's long‑awaited 2026 communication on pre‑enlargement policy reviews, entitled 'Preparing for a wider Union', was published on 6 October 2026. The communication proposes reinforcing gradual integration, which would be merit‑based and reversible and would require sufficient preparedness for accession in a given area, as well as strategic alignment with the EU. This would include full alignment with the EU's common foreign and security policy (CFSP) and sanctions regime. The document identifies priorities for deeper integration and organises them into four blocks (single market, competitiveness and economic security; energy, transport and digital connections; security, defence and resilience; and benefits for citizens and businesses).

With regard to the enlargement process, the communication recommends that the Council use qualified majority voting, instead of unanimity, for the opening of clusters and other intermediate steps in the accession process. Concluding negotiations would still require unanimity in the Council.

Concerning the content of future accession treaties, the Commission proposes safeguards to avoid post‑accession backsliding, as the accession process should ensure 'durable compliance with the rule of law, democracy and fundamental rights'. The safeguards are divided into sectoral safeguards (covering the economy, the internal market and justice and home affairs) and institutional safeguards, which would concern serious breaches of Article 2 TEU, which sets out EU values, and the principle of sincere cooperation. The institutional safeguards would apply for 15 years, and measures proposed by the Commission or requested through a reasoned request by Member States could be rejected by the Council acting by qualified majority within a limited time period.

On post‑accession EU governance, the communication proposes using passerelle clauses to move to qualified majority voting in selected policy areas, as well as using enhanced cooperation.

The Commission has announced that it will, on 4 November 2026, present a mapping of existing gradual integration instruments and set out the next steps, identifying instruments and opportunities to deepen integration in strategic sectors. It will also present roadmaps for the four countries most advanced in the accession process (Montenegro, Albania, Moldova and Ukraine), charting a path towards completing negotiations.

The European Council conclusions of 15‑16 October 2026 took note of the communication and called on the Council 'to analyse all strands and, on the basis of this analysis, to take work forward'.

Candidate countries' reactions to enlargement reform proposals

Candidate countries have had mixed and lukewarm reactions to 'reverse enlargement' and Member States' proposals. Ukraine had previously rejected a second-tier status in the EU. In response to the German and French models, described by Ukraine as 'shadow membership', Ukraine welcomed some of the potential benefits. Moldova has been willing to entertain the idea of accelerated progress towards accession. The country, however, remains committed to obtaining full membership status with the same rights as other Member States.

Albania was open to the prospect of fast‑track accession and a partial membership status under which it would relinquish its representation rights temporarily. This was part of a proposal co‑developed by Albania's Prime Minister Rama and Serbian President Vučić, who advocated accelerated integration to gain access to the EU internal market and the Schengen area in exchange for forgoing institutional representation rights and veto powers, arguing that it would keep the EU institutional balance intact. Commissioner Kos dismissed this proposal, stressing that economic integration demands the same reform standards. Later on, Albania's foreign minister reiterated the country's commitment to the merit‑based process, while suggesting that countries at an advanced stage of accession countries should be granted greater opportunities to engage (e.g. access to and participation in EU meetings, processes and institutions).

Montenegro, the frontrunner candidate, has deemed any change to the criteria for membership status unnecessary, focusing on attaining full membership. The country has already provisionally closed 21 out of the 33 negotiating chapters, and an ad hoc Council working party was established to draft the accession treaty. With Montenegro serving as a testing ground, the treaty might include long‑term safeguards and other provisions on the suspension of veto rights in the event of serious breaches (e.g. of the rule of law). While this is a response to the lessons learned from past enlargements, Montenegro reportedly supports new safeguards, 'only if they rest on objective criteria for assessing systemic breaches'. In terms of budgetary arrangements, the Commission has recently adopted a proposal for the country's financial package, underpinned by its proposal for the next EU long‑term budget. While the package still needs to be negotiated between the Council and Montenegro, once implemented upon accession, it would allow Montenegro to benefit from and contribute to the EU's policies and budget through a structured transition.

European Parliament positions

Parliament's resolution on the EU enlargement strategy of March 2026 maintains a preference for the current accession process, while calling for reform‑oriented, methodical and merit‑based approaches underpinned by clear roadmaps and timelines. It suggests greater use of 'gradual integration' to facilitate candidate countries' participation in EU common policies and cooperation with EU bodies (e.g. the European Public Prosecutor's Office). It also recommends that candidate countries' alignment with the CFSP and their role in EU security and defence be given greater consideration in the accession process, with full alignment leading to an invitation to attend Foreign Affairs Council summits as guests. The document also stresses the importance of the intra‑EU reform alongside the accession process to support both enlargement and the EU's capacity to function effectively. Highlighted measures include replacing unanimity with qualified majority voting at the intermediate steps of the accession process and a thorough review of the EU's sectoral policies.

An earlier Parliament resolution on the institutional consequences of the EU enlargement negotiations of October 2025 stressed the importance of pre‑enlargement EU reform and preparedness. First, it recommends that the EU's policies on the EU budget and agricultural and cohesion funding be recalibrated for enlargement, with the upcoming MFF including the necessary transitional and phasing‑in measures in these areas. Second, on institutional reform, the resolution suggests introducing a permanent mechanism for allocating seats in Parliament, as well as redefining qualified majority voting in the Council to improve the balance between large and small Member States and maintain higher thresholds for the most important and politically sensitive decisions. It envisages implementing institutional reforms through both targeted Treaty amendments and existing Treaty flexibilities (e.g. 'passerelle' clauses, enhanced cooperation and constructive abstention). Lastly, it recalls of the possibility of negotiating phased‑in solutions, temporary derogations and transition periods during accession talks.

Expert proposals for enlargement reform

Expert analyses of reforming EU enlargement policy have enriched this debate, with some proposed reform models focusing on 'gradual integration' while others explore alternative methodological and procedural avenues. The rationale for their proposals draws on several, sometimes contradictory, issues and conclusions:

The different proposals can be grouped into the categories listed below. Many of them propose moving to QMV in the Council, instead of unanimity, for the intermediate steps of the accession process.