Enlargement in Ukraine's case must go hand in hand with deeper defence reforms

“Enlargement in Ukraine's case must go hand in hand with deeper defence reforms and a rethinking of the EU as not just a normative power but one that can also credibly ensure its own security. That is the fundamental challenge”

 

Interview with Markus Kotzur

Markus Kotzur is Professor of European and International Law at Universität Hamburg and President of the Europa-Kolleg Hamburg, an interdisciplinary institution dedicated to research and advanced studies on European integration and international cooperation.  With a background in both legal scholarship and academic leadership, Professor Kotzur plays a prominent role in shaping the discourse on European constitutional development and the external relations of the European Union.

His research interests lie at the intersection of European law, international law, and comparative constitutionalism. He has written extensively on the constitutional foundations of the EU legal order, the evolving nature of EU external action, and the legal dimensions of globalization. His work frequently engages with questions of legal integration, democratic legitimacy, and the role of law in managing complex cross-border governance. As President of the Europa-Kolleg, he is actively involved in interdisciplinary research initiatives and international academic cooperation.

Professor Kotzur is a sought-after speaker and commentator on European legal affairs, regularly contributing to scholarly conferences, academic publications, and expert policy discussions in Germany and beyond. In addition to his academic roles, he has served on editorial boards and advisory committees related to EU legal studies.

 

O. Kandyuk: Do you think that the EU needs reform to start the Enlargement? Or can the existing mechanism handle the new round?

M. Kotzur: I believe some reforms are required, even though they are difficult to achieve. In particular, the shift towards majority voting in decision-making processes is essential. The larger the European Union becomes the more difficult and ineffective the unanimity principle will be. Therefore, I believe that the extension of majority voting, including in the area of foreign policy, should be considered.

One idea in this direction was proposed by former Latvian President Egils Levits, who is also a scholar of European law. He suggested that member states could retain a veto power in cases where vital national interests are at stake, but that majority voting should otherwise be the standard procedure within the European Union.

This, in my view, is the most important reform requirement in the Treaties. I am not very optimistic about other proposals, such as strengthening Article 7 TEU or introducing a clause that would allow for the expulsion of a member state that fails to adhere to the Union's values. That seems unlikely to be realised. But reforming the unanimity principle and establishing majority voting as the norm is, in my view, essential.

O. Kandyuk: But would such reform require a new phase of democratic legitimation? For example, should the mandate of the European Parliament be strengthened, or should there be broader public consultations on key integration issues?

M. Kotzur: I think, particularly in the context of enlargement, we already have a strong level of democratic legitimacy. All relevant actors are involved, and there is a broad public debate. The European Parliament plays a role, as do the European institutions and national parliaments. Therefore, I do not believe democratic legitimacy is the core issue here.

Even when a new member state joins the European Union, the architecture of two pillars –where both the peoples of Europe and the member states legitimise the Union – remains intact, regardless of the number of member states. Thus, I would argue that no urgent reforms are necessary for the enlargement process in terms of legitimacy. Democratic legitimacy is sufficiently guaranteed, particularly because all democratically elected institutions of the European Union are already involved in decisions regarding enlargement.

O. Kandyuk: To what extent is it advisable to further develop a European constitutional practice–for instance, by strengthening the role of the European Court of Justice in political conflicts? Could this risk heightening tensions with national sovereignties?

M. Kotzur: The constitutional debate that began at the turn of the millennium has been both helpful and important. It enabled the European Union to recognise that, even if not the entire treaty, many provisions within the Treaties have constitutional significance. This is true for fundamental principles such as democracy, the rule of law, and human rights, as well as for the institutional framework. For this reason, the constitutional narrative has proven to be valuable, and I believe we should not abandon it. Doing so would undermine the entire integration framework.

The European Union is, to a certain extent, a constitutionalised entity, and I strongly support that thesis. In this context, the European Court of Justice functions, in some respects, as a constitutional court that deals with typical constitutional law issues. That is why I have always been very critical of member states that harshly criticise the Court of Justice.

Of course, conflicts exist. We saw this, for example, in the PSPP/Weiss judgment, when the German Federal Constitutional Court challenged the European Court of Justice by declaring its ruling an ultra vires act, on the grounds that it violated the general structure of the principle of proportionality. I strongly criticised that judgment. There is a significant difference between a potentially incorrect judgment – a possible misinterpretation of proportionality – and an ultra vires act. Courts may very well act within their competencies and still deliver flawed decisions that may later require revision or correction. That is part of a functioning judicial process.

The aggressive responses from the constitutional courts of Hungary and Poland towards the European Court of Justice are also deeply concerning. They are detrimental to the Union. We must be clear that the principle of the supremacy of EU law is fundamental to the functioning of the European Union.

Unfortunately, given current political tensions, including rising populist opposition to Brussels and Luxembourg, this conflict is unlikely to disappear quickly. It is a difficult and sensitive issue to argue politically. Yet we must continue to affirm that the European Union can withstand political contestation. Such contestation is healthy–it is good to criticise and debate–but we must adhere to foundational constitutional principles. That includes respecting and abiding by the decisions of the courts.

I would defend this point strongly, despite the political challenges it poses, especially given the rise of right-wing populism. Nonetheless, upholding these principles remains essential.

O. Kandyuk: In light of the war in Ukraine, how should the EU redefine its enlargement process to align with the current geopolitical landscape while maintaining its democratic and normative principles?

M. Kotzur: That is indeed an extremely difficult question, as the European Union has no prior experience in such a context. If we look at the history of enlargement, the EU has always followed a “learning by doing” approach – gradually structuring the negotiations, establishing the chapters that need to be addressed, and defining what is negotiable and what is not.

Traditionally, it was generally agreed that the EU would not consider admitting a country engaged in an active military conflict with a third state. However, the situation we face now –an aggressive war initiated by the Russian Federation and President Putin against Ukraine – is fundamentally different. The European Union decided to accept the candidate status of a country which is in war with Russia. And we do not know when the war will end or what form a peace agreement might take – or whether it would be stable at all.

This is an entirely new situation for the EU. There is no blueprint. From my perspective, it is crucial that the Union adopts a realistic stance. The EU’s Common Security and Defence Policy, particularly Article 42(7) on mutual defence, needs to be taken seriously. We must reconsider our security guarantees.

We should also be realistic, the European Union will not be able to force NATO to accept the Ukraine as a new member state. Therefore, alternative mechanisms for ensuring stability within the Union – and for a future post-war Ukraine – must be considered. But at the moment in the association context and in the enlargement negotiations the European Union should really concentrate on the other chapters, on the other reforms.

We must monitor how the situation evolves and ensure the EU itself strengthens its role as a potential geopolitical actor. That includes increased investment in defence and military capabilities. Of course, this depends on the member states and intersects with broader debates on a European army.

And that brings me back to the first question, enlargement in Ukraine's case must go hand in hand with deeper defence reforms and a rethinking of the EU as not just a normative power but one that can also credibly ensure its own security. That is the fundamental challenge. The EU should proceed chapter by chapter in the accession talks and assess the security situation once all chapters have been negotiated. Whatever future peace process emerges, European neighbours will inevitably be involved, so everything must be approached step by step.

O. Kandyuk: Considering that we are facing a new potential wave of EU enlargement, how do you assess the impact of the most recent enlargements on the legal and institutional effectiveness of the Union?

M. Kotzur: I think that's a very tricky question. It is quite clear that unanimity is not a viable option for the future. It remains one of the EU's most significant structural problems.

One key point for institutional reform is the composition of the European Commission. If a new member state joins, it adds another Commissioner. That structure is not optimal for an executive body at the EU level. We should seriously reconsider it in the context of reform.

There is also the longstanding question of whether there is a “natural limit” to how large the Union can grow. More judges, more Council members–it all adds complexity. However, if we look at the United States, a federation of 50 states functions effectively. This shows that size need not be the limiting factor.

Therefore, the EU can remain functional even as it expands, provided necessary institutional reforms are enacted. It is crucial to prevent a single member state from obstructing progress. For instance, in the case of sanctions against Russia, Hungary has exercised disproportionate power, leading to uncomfortable bargaining dynamics–essentially trading political support for financial concessions. This practice must be overcome.

That brings us back to the importance of majority voting. I would not argue that there is a fixed threshold beyond which the EU becomes unmanageable. But there is no doubt that reforms are necessary to ensure smooth governance.

O. Kandyuk: Since we are speaking about this, do you think that the European Union should become a federation in the end? Do you think it is a feasible perspective?

M. Kotzur: I do not see it as realistic at the moment. There is a profound lack of political will among the member states.

I personally have some sympathy for the federal idea and consider such “out-of-the-box” thinking intellectually valuable. Academics should continue exploring these possibilities.

However, politically speaking, the idea of a federal Europe is far from achievable today. The term "federation" triggers resistance in public discourse, and not only from right-wing parties. There is currently no majority support for it across member states.

So, while I do not think federalist ideas should be discarded entirely, they are not the focus of current political debates.

O. Kandyuk: How do you assess the EU's role in protecting democracy and the rule of law within its borders? How effective are mechanisms such as Article 7 of the EU Treaty?

M. Kotzur: Article 7 has not proven to be particularly effective, mainly because it is itself based on unanimity. It is a severe sanction, and the EU has been reluctant to invoke it fully.

More effective has been Article 258 – cases brought before the European Court of Justice. These provide the EU with legal leverage.

Additionally, the newer rule-of-law conditionality mechanism has shown some promise. It represents a constructive step in the right direction. The portrayal of the EU as a “toothless tiger” is not entirely accurate. The Union has sought creative and workable approaches. The financial conditionality mechanism, has demonstrated real impact and can influence behaviour within member states.

Of course, in the long run, it might make sense to introduce the possibility of expelling a member state that abandons the democratic rule of law and fundamental rights to such a degree that it no longer aligns with the EU’s foundational values. But the political likelihood of such treaty reform is very low at present.

For now, the conditionality mechanisms remain the most effective tool, especially given the limitations of Article 7.

O. Kandyuk: In your article On the eve of the European Parliament elections (2014), you questioned democratic legitimacy in EU policymaking. A decade later, how can the EU address its democratic deficit in multi-level governance?

M. Kotzur: The Lisbon Treaty was a significant step forward, strengthening the democratic legitimacy of the EU by giving the European Parliament real legislative powers.

I think this is a very important step forward. From a formal perspective, the EU’s dual legitimacy model is robust: a directly elected European Parliament, alongside the Council representing democratically elected national governments, so we have that indirect chain of legitimacy. This structure is conceptually strong.

However, I would point to a different kind of deficit. If you look at topics such as deliberative democracy, one of the deficits is that the European Union for a way too long time has been conceived as a rather functionalist and very technical integration scheme, which was not politicized.

This contrasts with national politics, where citizens are accustomed to vibrant debate, party competition, and open controversy. Such dynamics are weak at the EU level. Instead, we see mistrust toward Brussels and a lack of public engagement with EU policymaking.

While citizens vote in European elections, their choices are shaped more by national political contexts than by EU-level party programmes or debates. Genuine transnational politics remain underdeveloped.

To address this, we need to politicise the EU more clearly–treat it as a political actor in its own right and communicate its decisions in the same way we do national legislation. Parliamentary debates and new directives should be publicly scrutinised and discussed across member states.

This is the core of the problem. The formal democratic instruments are in place. But without vibrant, deliberative processes–without real political contestation–they lack resonance with the public.

The Conference on the Future of Europe was a step in the right direction, aiming to improve citizen participation. But it coincided with the COVID-19 pandemic and did not achieve significant public impact. Most students I teach, even those specialising in EU law, are unaware it even took place.

It was a well-intentioned idea that failed in practice. We must therefore find new, more effective ways to generate real, European-level public debate–moving beyond parallel national conversations about Europe. We have harsh debates, but we have a German debate on Europe, and we have a French debate on Europe, and we have a Polish debate on Europe. But we hardly have a European debate. This is what, from my perspective, is missing most.

O. Kandyuk: Your concept of the 'democratic Rechtsstaat' envisions a flexible legal order. What role does this flexibility play in integrating new member states. How do you reconcile responsiveness with legal certainty in EU external relations, especially when dealing with rule-of-law backsliders?

M. Kotzur: Flexibility should not be misunderstood. The rule of law is a foundational principle, and we must adhere to it strictly, particularly with regard to stability and legal certainty. Flexibility can be achieved through a certain degree of differentiated integration – for instance, by allowing opt-outs in specific policy areas such as the monetary union. Some member states may choose not to participate in all aspects of integration.

Flexibility is also necessary to accommodate national and constitutional identities, allowing member states to develop their own understanding of democracy and the rule of law. However, the core principles must remain non-negotiable. If we were to compromise on them, the legitimacy of the entire European Union would be at stake.

These two dimensions of legitimacy – through the directly elected European Parliament and the indirectly legitimised Council – presupposes that all member states are functioning democracies based on the rule of law and human rights. If that premise is undermined, the entire institutional structure loses credibility. One “poisonous fruit” can spoil the whole dish. Therefore, I would be strongly opposed to flexibility in this regard. We must remain acutely aware of the risks of compromising these foundational values.

In terms of foreign and defence policy, the EU is also a rule-of-law-based actor. This implies a commitment to public international law. But foreign policy and defense policy are also about political interests, and we should be open and also quite clear to address political interests. The European Union has been very strong, also given the articles in the TEU and the TFEU to talk about the values based foreign policy of a normative power, which is wonderful.

But I think it would be very naive to ignore that any foreign policy is, of course, also interest driven. And I think we should make that more precise and we should make that more outspoken in our debates.

O. Kandyuk: In your chapter 'Grundfragen einer europäischen Sicherheitspolitik', you discuss the legal foundations of European security. Which EU legal mechanisms, in your view, require reform to enable effective collective security without undermining national sovereignty?

M. Kotzur: That is a super difficult question. I am not convinced that a fully-fledged European army would be the decisive solution. Expecting member states to relinquish control over their armed forces is a significant demand, and I am sceptical about its feasibility.

However, closer cooperation and the strengthening of existing frameworks – such as PESCO – are important and should be advanced. Greater harmonisation in military procurement is also essential. It makes little sense for the EU to maintain dozens of different weapon and tank systems. Closer coordination would enhance operational effectiveness and strategic coherence.

In addition, we cannot ignore the importance of the United Kingdom in European defence. It is very detrimental that the UK left the EU, but the recent agreement on defence cooperation is a positive development. Because we need to be clear, only two countries in Europe possess nuclear weapons – France and the UK – and any discussion about a nuclear deterrent must include both. A stable, reliable partnership with the UK remains a key pillar of European defence.

O. Kandyuk: In Solidarity as a Legal Concept (2017), you criticize the vague use of solidarity in the Lisbon Treaty. How should the EU implement solidarity to reflect both moral obligations and the institutional allocation of responsibilities?

M. Kotzur: Solidarity is by nature a vague and multi-dimensional concept. It may function as a moral obligation between peoples or, particularly in the context of inter-state relations, it may amount to a legal obligation. The EU should strive to make solidarity more concrete.

In the field of defence, Article 42(7) TEU outlines a serious commitment to mutual assistance. Beyond that, in areas such as the monetary union or crisis response, the EU must recognise that cooperation – a key integration mechanism – can only succeed when it is based on solidarity. Without it, member states will ultimately be unwilling to engage in meaningful cooperation.

Therefore, both scholars and policymakers should work to specify what solidarity entails in different domains – defence, social cohesion, migration, and beyond. Developing concrete definitions and practical examples will help translate solidarity from an abstract principle into a functioning legal and political norm.

O. Kandyuk: Could 'solidarity obligations' become a mandatory criterion for accession–such as a required contribution to migration policy or a crisis containment fund?

M. Kotzur: In theory, yes. But if the EU wants to make solidarity a legal obligation for accession candidates, it must also be willing to apply the same standard to existing member states. It would not be credible to demand more from new members than what is currently expected of existing ones. If solidarity remains non-binding for current members, then requiring legal commitments from newcomers would be unjust and unsustainable.

Therefore, introducing solidarity as a legal obligation would necessitate broader institutional reform and would have to include both old and new member states. Only on this basis could such a criterion be meaningfully implemented.

O. Kandyuk: But, do you think such a development is realistic?

M. Kotzur: I can see that as a visible perspective, because it's a pragmatic perspective. The EU has already realised that it needs financial resources for major initiatives – whether for the Green Deal, industrial policy, or the reconstruction of Ukraine. We have also witnessed a shift in political attitudes, particularly following Russia’s war of aggression against Ukraine.

Member states have shown a willingness to invest substantially in defence and infrastructure, including by accepting public debt. In Germany, the establishment of the Sondervermögen – a special fund of €100 billion– marked a profound shift in political mentality, moving away from the traditional austerity mindset. This change is now also visible at the EU level.

Such a shift makes the creation of a solidarity fund or similar mechanisms far more plausible today than it was 10 years ago.

O. Kandyuk: And one final question I often pose to experts concerns future scenarios. If you were to outline two or three possible paths for Ukraine’s integration into the EU, what scenarios would you consider?

M. Kotzur: Also a very difficult question. One realistic scenario is full EU membership for Ukraine. I do not consider this impossible. The EU understands that the promise inherent in candidate status must be taken seriously. After an extended negotiation period, Ukraine could very well become a full member. This is a fundamentally different situation from the Turkish case, and the comparison is not appropriate.

A second scenario would involve a very close association based on the existing Association Agreement – a form of privileged partnership. This would almost certainly include concrete security and defence arrangements. It is important to note that the strategic calculus here is not only about Ukraine’s interest in EU membership for protection against Russia. It is also in the EU’s interest to integrate Ukraine in order to reinforce European security. A reversal in Ukraine’s geopolitical orientation would be disastrous for EU security – particularly for the Baltic States. Thus, Ukraine’s alignment is of mutual strategic importance.

The third scenario, of course, is always a complete failure. I think we need to be realistic, that can always be a scenario. But such a failure would also be deeply damaging to the EU – not just in terms of enlargement, but with regard to its broader integration capacity and credibility.

The European Union can no longer afford to be blind when it comes to security cooperation, security infrastructure, and how it positions itself towards Russia – also as a military actor. We need to be realistic. It's not just about Trump or the most recent U.S. administration. The fact is, the United States is turning away from Europe. The Asia-Pacific and Southeast Asia regions are now much more central to their strategic interests.

And they have strong arguments: Europe is economically strong; Europe has power – so why doesn’t it take responsibility for its own defence? Why should the U.S. continue to defend Europe, as it has done for the past 60 or 70 years? And at the same time, whenever something goes wrong, Europeans blame the “bad Americans.”

There’s also a kind of comfort in Europe – a reluctance to deal with the morally difficult or politically dirty aspects of security. Europeans often come forward with human rights, values, and moral principles, while expecting the U.S. to do the hard work. But when the U.S. refuses, Europeans are disappointed.

I think that’s the key lesson the European Union has learned. And if the EU doesn’t respond accordingly – by assuming more responsibility and acting as a serious security player – then, in the end, the integration process itself will be at risk of failure.