How can one reconcile the geopolitical urgency of moving forward with EU enlargement, the volatility and fragmentation of internal European politics, and the union’s legal and institutional rigidity? This is the challenge of enlargement in the 2020s. National governments, the European Commission, and think tanks have suggested various ways to resolve this conundrum. Some of the proposed remedies are unlikely to work, others have potential but are controversial, while still others have broad support but are difficult to implement.

There is no silver bullet, but there is a chance that a combination of procedural and substantive adjustments can move the process forward. A ratified EU accession treaty will continue to be the key to full membership, but a lot of integration can happen without this step.

The Dynamics of the Enlargement Debate

The EU enlargement debate is currently shaped by two dynamics. The first is geopolitics, which makes it necessary to anchor Ukraine and Moldova as rapidly as possible in the EU and to finally move forward with enlargement to the Western Balkans. The other is the fragmentation of Europe’s political landscape, which makes coherent action by the EU’s member states very difficult. Since the last EU accession of Croatia in 2013, European politics have become more contested and volatile. New divisions have opened up and solidarity has diminished. Governments often leverage EU projects to push national objectives. Radical-right parties, most of them skeptical toward any deepening or widening of European integration, have gained ground and entered the government in some countries.

These two dynamics are increasing both the political salience of enlargement and the difficulty of achieving positive outcomes. The current volatility of European politics collides with the EU’s legal and institutional rigidity. The Treaty on European Union puts the accession of new members under a double lock. It requires, first, the unanimous approval of an accession treaty by all EU governments and, second, that treaty’s ratification by the member states and the acceding country. The ambivalence of many governments toward enlargement has further burdened the process with restrictive rules that make technical steps, such as the opening and closing of negotiation chapters, subject to unanimous decisions. Under current procedures, any accession process has to pass through dozens of veto points.

EU enlargement has always been a difficult endeavor. Almost all of the seven previous enlargement rounds were held up by bilateral disputes between individual member states and candidates or by linkages with other EU projects. However, in the end, the interest of a majority of member states in the economic and political benefits of a larger union prevailed over the hesitations of a minority. And when an accession treaty had finally been agreed on, ratification was normally a smooth process, taking an average of roughly fourteen months.

The New Vulnerability of EU Enlargement

Both the negotiation phase of enlargement and the prospects for ratification once an accession treaty has been concluded look significantly more challenging today than in the past. Member states have a stronger propensity than before to make their support for accession conditional on the resolution of bilateral issues. Not only has Hungary blocked the start of accession talks with Ukraine, but even countries that support their neighbors’ entry have also set preconditions that often stem from historical disputes. Croatia has made such demands of Montenegro, Poland of Ukraine, Greece of Albania, and Bulgaria of North Macedonia. The rise of nationalist parties in many EU countries makes it more difficult to overcome these obstacles.

A considerable number of member states take the view that enlargement needs to be accompanied by reforms of EU policies and institutions to ensure the effectiveness of a larger union. The commission has promised a report on these matters but, aware of its sensitivity, has repeatedly postponed its publication. One concern is that enlargement could result in the appearance of more disruptors on the EU’s political scene akin to outgoing Hungarian Prime Minister Viktor Orbán. Many countries therefore demand a move toward more decisionmaking by majority instead of by unanimity. Euroskeptic governments and political parties committed to preserving national sovereignty are certain to resist such proposals. A blockage on the EU’s internal reform can easily slow progress toward further accessions.

One particular challenge of today’s enlargement agenda is the tension between the urgency of bringing Ukraine on board and the time required to prepare the country’s institutions to apply the EU’s legislation fully and effectively. For Ukrainian President Volodymyr Zelensky, having a credible prospect of economic recovery and internal stability as part of the EU is crucial for Ukraine’s future success. EU membership is seen in Kyiv as a key element of postconflict security guarantees. Rather than vague commitments of an open-ended multiannual negotiation process, Ukraine demands a clear time frame for early accession. Member states seem reluctant to commit to a target date for accession and insist that the process needs to remain merit based.

Enlargement is also intrinsically bound up with the EU’s future financing. The commission’s proposal for the 2028–2034 multiannual budget earmarks roughly €43 billion ($50 billion) for the union’s enlargement and neighborhood pillar as well as a funding stream of €100 billion ($117 billion) for Ukraine’s reconstruction. The proposal also includes a revision clause to allow the budget to be adjusted in case new countries join before 2034. The proposal provides for a significant increase in the EU’s overall funding, which is strongly opposed by several governments. The negotiations, which will probably reach their decisive stage in 2027, are likely to be highly controversial and could have a considerable impact on the progress of enlargement.

And even if all of these constraints and obstacles can be overcome and accession treaties are agreed on and signed, ratification by all EU members can hardly be taken for granted. These days, government majorities are unstable and parties that are intrinsically hostile to EU projects and policies have become stronger. The threshold for ratification is particularly high in France, where the constitution requires either a three-fifths majority in both houses of parliament or a positive outcome of a referendum. Governments might take ratification hostage to extract concessions on other projects—as happened in NATO when Turkey and Hungary dragged out Sweden’s 2024 accession to the alliance—or they might come under pressure from populist movements to hold referendums. Given the volatility of European politics, the risk of severe delays and blockages is significant.

Options for Overcoming the Obstacles

Most stakeholders in the EU enlargement process are well aware of the risks. To move the process forward despite these difficulties, the various parties involved have developed several strategies and ideas.

Low-Hanging Fruit First

In its November 2025 report on enlargement, the commission expressed its hope that accession negotiations with Montenegro could be wrapped up by the end of 2026 and those with Albania one year later. Moldova, with its committed pro-EU government, could conceivably catch up. Should Iceland decide in its August 2026 referendum to reactivate its application for EU membership, it should also be able to join this group. As a member of the European Economic Area (EEA), Iceland already participates in the European internal market, which should make its entry into the EU easier.

The commission’s clear hope is that a limited number of small countries—ones that can be easily absorbed into the EU and do not face significant hostility from existing members—could be brought into the union around 2030, thus restoring the credibility of the process.

The plan may succeed, but major uncertainties remain. Both Montenegro and Albania have governance issues that could derail the commission’s ambitious time frame. Linkages with EU institutional and policy reforms could still pose problems. And even a small avant-garde of applicants might not be able to overcome the hurdle of ratification, in particular in highly polarized France. The other problem of the “low-hanging fruit” scheme is that it does not address the urgency of anchoring Ukraine in the EU. Also, there is a considerable risk that the remaining candidates, rather than being encouraged, will feel neglected and left behind.

Membership Lite

European Commission President Ursula von der Leyen has always been a champion of Ukraine’s EU perspective. It is therefore unsurprising that the commission is looking for ways to address Kyiv’s wish for accelerated integration into the EU. One idea that has been discussed with member states has become known as reverse enlargement. This provides for a new type of membership lite that would postpone a candidate’s full integration into the more demanding EU policies until the country’s national legislation and institutions are ready to apply EU law fully and effectively. Until then, the new member’s decisionmaking rights would be limited to the areas in which it already participates.

Member states’ responses to the concept of reverse enlargement were skeptical, but many governments recognize the need to safeguard Ukraine’s European orientation. Germany and France have recently proposed an even lighter form of early association for Ukraine. They highlight the symbolic value of such a new status—called “associated member” by Germany and “integrated state” by France—which would be based on a political decision, not a treaty. This option would postpone Kyiv’s participation in most EU policies until further progress is made toward accession but would hold out the promise of gradually phasing in financial assistance. According to German Chancellor Friedrich Merz, the EU is also considering granting Ukraine observer status in the EU institutions at an early point in the process.

Staged Accession

Think tanks and NGOs have presented various concepts of “staged accession.” Most of these proposals provide for different stages of membership, through which a candidate’s access to EU structural funds, participation in EU programs, and decisionmaking rights would be gradually ramped up according to the progress of its reforms. The proposals aim at strengthening incentives for reforms while allaying existing members’ concerns that accessions of candidates that are not fully prepared would disrupt the union’s work.

So far, EU member states have been disinclined to radically revamp the current enlargement methodology. However, the idea that accession treaties could include special rules for new members has met with considerable interest, including in the commission. Such rules could, for instance, provide for stronger rule-of-law conditionality that could reduce the risk of democratic backsliding. There could also be time-limited constraints on the right of new members to veto EU decisions. This might alleviate existing members’ concerns about disruptive newcomers and thus ease ratification. Member states and some Western Balkan countries have expressed openness to such ideas.

The Internal Market First

A more radical approach was proposed in a joint editorial in February 2026 by Serbian President Aleksandar Vučić and Albanian Prime Minister Edi Rama. They expressed a preference for accelerated integration into the EU’s internal market and the Schengen passport-free travel area rather than moving directly toward full membership. Think tanks have promoted similar ideas. The main argument is that prioritizing candidates’ participation in the internal market would not affect the EU decisionmaking process and thus obviate the need for institutional reforms.

While this is true, it is not evident that candidates’ full integration into the internal market could be achieved much faster than accession. The need for reliable implementation of EU legislation would be essentially the same. The requirement for high rule-of-law standards would also apply, as an independent and effective judiciary is crucial for the functioning of the internal market.

Also, entry into the internal market—possibly through membership in the European Free Trade Association (EFTA), which together with the EU forms the EEA—would require a treaty that would be subject to ratification. Finally, the fact that Iceland is considering renewing its membership application shows that being obliged to implement EU decisions without being able to influence them is a rather unsatisfactory arrangement.

Majority Voting on Enlargement

Frustrated at the proliferation of blockages both on foreign and security policy and on enlargement, a group of member states is advocating replacing unanimity with majority voting in many of these areas. For enlargement, this move would preserve unanimity for decisions on starting and ending negotiations but would introduce majority voting for most of the intermediate steps. Different concepts for the types of majority that would be required for enlargement decisions are under discussion.

Majority voting could be introduced without changing the EU treaties, for instance by adjusting the so-called negotiating frameworks—the EU decisions that underlie accession talks. There is, however, one fundamental problem: Majority voting can be introduced only by a unanimous decision by all member states.

There is considerable support for majority voting on enlargement, including from the president of the European Council, António Costa. But several EU members are very reluctant. Some worry about the risk of being outvoted on enlargement decisions of direct concern to them. Cyprus’s complex relations with Turkey are a case in point. Other members may wish to preserve the possibility of leveraging enlargement decisions to obtain bilateral concessions from particular candidates. This opposition is unlikely to be overcome soon. At most, it seems possible to moderately reduce the number of veto points. A game-changing move toward majority voting currently seems out of reach.

Gradual Integration

Gradual integration—the incremental sharing of some of the benefits of EU membership with candidates ahead of their accession—enjoys almost universal support among member states and candidates. The basic idea has been part of the enlargement process ever since EU association agreements were negotiated in the 1990s. Many programs and projects in diverse areas of European integration have been gradually opened up to candidate countries.

In recent years, as achieving full membership has become more difficult and uncertain, the case for gradual integration has become stronger. Offering concrete benefits to acceding states that deliver on reforms provides incentives for further progress. Allowing candidate countries to take part in the work of EU bodies helps their administrations to familiarize themselves with the functioning of the EU. Structured cooperation between acceding states and members fosters confidence and reduces hostility to enlargement.

The commission has given more substance to gradual integration through the EU’s Growth Plans for the Western Balkans and Moldova and its Priority Action Plan for Ukraine. These schemes offer financial support and participation in EU programs and policies, conditional on the achievement of reform goals agreed on by the EU and each candidate country. These plans have begun to render results, such as the inclusion of candidates in the Single Euro Payments Area for euro-denominated bank transfers or in the EU’s scheme for low-cost cell phone roaming. The benefits of these steps are undeniable, though they have not yet resulted in a significant increase in the pace of reforms. In fact, European Commissioner for Enlargement Marta Kos warned in April 2026 that a substantial part of growth plan funding would be permanently lost unless the promised reforms are rapidly implemented.

What is more, on the central promise—the gradual opening of parts of the internal market—progress has been excruciatingly slow. The hurdles that candidates have to clear are high: full alignment with EU law, the ability to implement it, and effective safeguards for its correct application, including a role for the European Court of Justice. Such steps also need a solid legal basis in the form of agreements that have to be negotiated and ratified by both sides. The commission and a few candidates have started to prepare such agreements. These will focus mostly on elements of the single market for goods, allowing candidates to access European supply chains. But so far, no agreements have been concluded.

For countries that hope to accede to the EU shortly and whose administrative capacity is already stretched by the demands of enlargement negotiations, the extra effort of working on gradual integration is hard to justify. For those farther behind, the technical difficulty of the task can be daunting. The commission, too, faces major problems of institutional capacity, as pursuing multiple projects of gradual integration in parallel with negotiating accession treaties compounds an already high workload. Von der Leyen and Kos probably regard getting candidate countries into the EU—or, at least, very close to it—as the main criterion for the success of their mandates. The commission consequently prioritizes accession negotiations over an energetic push on gradual integration.

In light of the uncertainty of enlargement today, it nonetheless seems necessary to expand and intensify the work on gradual integration. While the legal and technical challenges are similar to those of the enlargement process itself, the politics look a lot easier. For countries farther back in the line, gradual integration offers the only realistic chance of moving forward. For the front-runners, it provides insurance in case their accession is held up. The economic and political benefits of including candidate countries in parts of the internal market can be significant. More practical experience should help clarify the legal issues and will eventually make the task easier.

Five Steps for Making Progress

EU members and candidates alike are struggling to adjust the union’s enlargement methods and instruments to the challenging environment of today. There is no single solution that will make enlargement fit for purpose in the 2020s. Different approaches will have to be combined or pursued in parallel. Five points sketch out a possible way forward.

First, anchoring Ukraine and Moldova firmly in the union is crucial for safeguarding Europe’s security against the threat from Russia. While member states have shown little enthusiasm for the commission’s idea of reverse enlargement, many understand that the traditional enlargement methodology does not address the urgency of bringing Ukraine on board. What is needed is a credible and substantial set of measures that demonstrate the EU’s commitment to fully integrate these countries. Zelensky has already made clear that purely symbolic steps will not suffice. The EU should therefore offer some sort of membership lite, which would include Kyiv’s and Chişinău’s participation in several EU policies (based on gradual integration), substantial financial assistance, and observer status in EU meetings.

Such a package would not require a fully ratified treaty. Given the need to bring Ukraine and Moldova in quickly, ratification might take too long. According to past practice, a signed accession treaty—which, in the cases of Ukraine and Moldova, could initially amount to a framework agreement—already offers the acceding state the role of observer in the EU institutions. Ratification by the members could wait until the candidate’s legislative alignment and institutional adaptation were sufficiently advanced and adequate rule-of-law standards were ensured. Military security will play a crucial role in Ukraine’s accession and could be the subject of a separate treaty arrangement. From the start, the country should participate fully in all EU programs and discussions relevant to military security. Including Ukraine in a new European security council would confirm the country’s indispensable role in protecting Europe from the Russian threat.

Second, if the EU moves toward granting membership lite to Ukraine and Moldova, it would make sense to offer this model to the Western Balkan countries as well. This would reduce the risk that the accessions of a few countries, which happen not to be held back by unresolved bilateral or status issues, might result in a new division of the region. The process would remain merit-based, as each country’s participation in the internal market would depend on the pace of its reforms and its legislative alignment. But at the same time, the EU would confirm and encourage the European orientation of all countries in the region.

Of course, member states may not be ready to apply an innovative approach to all candidate countries. If the Western Balkans need to go through the traditional enlargement process, the EU—in particular, the commission—must avoid the mistake of focusing all its efforts on the front-runners but must engage equally in moving all the countries in the region along. Expanding and intensifying efforts on gradual integration can play a critical role in this regard.

Third, the union needs to examine how to strengthen its relationship with Turkey. Partly because of Ankara’s democratic backsliding and rule-of-law deficits, and partly because of deep skepticism in several EU countries, Turkey’s membership perspective has drifted into the background. Accession negotiations have been at a standstill since 2018. But as Turkey’s strategic importance and economic potential have grown significantly, so too has the EU’s interest in a strong and constructive partnership. The country already participates successfully in several EU programs and agencies. Once internal political developments in Turkey allow, both sides should move quickly to put the relationship on a new basis, which could provide for a significant degree of Turkish participation in European integration.

Fourth, as the great majority of today’s candidates aim for full membership, the ratification of an accession treaty by all member states remains an unavoidable moment of truth. Limiting the veto rights of new members during an initial period and imposing tougher rule-of-law conditionality could reduce opposition in existing members. As there appears to be considerable openness among the candidates to such ideas, this approach is worth exploring.

That said, ensuring successful ratification in today’s contested political landscape first and foremost requires an active and sustained effort of public communication. The primary responsibility for preparing the public for EU enlargement lies with the governments of the member states. Many governments have been reluctant to talk about a subject that is unpopular in their countries. Much will also depend on whether the acceding countries can present themselves as valuable partners in the common European project. The EU institutions certainly have to share in this effort.

Finally, it is likely that not all ten current candidate countries and potential candidates will eventually become EU members. As the example of Georgia shows, internal political developments can deflect a country from its European path. For others, resistance within the EU or from particular member states could prove insurmountable. However, as the historical record shows, there can be good reasons to involve such countries in European integration. The Schengen area has several non-EU members. The EEA has offered Iceland, Liechtenstein, and Norway access to the internal market. The EU is currently reopening some of its policies for the UK and in March 2026 signed a broad package of new agreements with Switzerland.

To judge from current debates on the future of the EU, it seems evident that the union will need to move toward greater differentiation and flexibility in its policies and structures. Internal divisions and external challenges leave no other choice. Groups of member states are likely to take the lead on future integration projects. Not all EU members will participate in these initiatives, but sometimes the involvement of nonmembers will be important for their success.

In line with this logic, the EU should prepare itself for variable levels of engagement and integration in its external relations, too. In all likelihood, a ratified accession treaty will remain crucial to gain access to the core of European integration. But a lot of integration could be available without full EU membership.