Recent contributions to this series have shown how enlargement has returned to the centre of European geopolitics. Vera Tika argues that the emerging model of gradual accession is transforming the meaning of EU membership from a binary status separating insiders from outsiders into a continuum of differentiated participation
The history of European integration is also a history of changing meanings of enlargement.
For much of its history, enlargement was associated with democratic consolidation and political inclusion. The accession of Southern European democracies, and later the post-communist states of Central and Eastern Europe, reflected a bargain: countries that adopted EU rules and fulfilled accession criteria would eventually become full and equal members of the Union.
This principle underpinned the EU’s transformative power. Enlargement was credible because membership was credible. Today, however, the rationale for enlargement is gradually shifting. Whereas previous enlargements were primarily justified as instruments of democratic transformation, enlargement is increasingly driven by geopolitical considerations.
Russia’s full-scale invasion of Ukraine has revived enlargement as a strategic instrument for strengthening European security, stabilising neighbouring regions, and extending the Union’s influence. As Veronica Anghel argued in this series, enlargement has become a geopolitical necessity.
The central challenge is how to make enlargement work.
The renewed urgency of enlargement coincides with growing concerns about the EU’s capacity to function effectively after further expansion.
Hungary’s democratic backsliding raised fears that future enlargements could worsen EU institutional paralysis. This is particularly true in policy areas that still rely on unanimity. As a result, European policymakers have become increasingly interested in models of gradual accession.
Under such approaches, candidate countries could gain access to selected EU programmes, funding mechanisms, agencies and policy areas before becoming full members. Following Russia’s invasion of Ukraine, these discussions gained momentum. Emmanuel Macron’s proposal for a European Political Community and the European Commission’s support for phased integration both reflect efforts to bring candidate countries closer to the Union before accession.
Nowadays, enlargement is increasingly viewed as a strategic instrument of geopolitical stabilisation rather than solely a mechanism of democratic transformation
More recently, Germany's Chancellor Friedrich Merz has reaffirmed his country’s commitment to advancing the accession of Western Balkan countries, highlighting how enlargement is increasingly viewed as a strategic instrument of geopolitical stabilisation.
From a strategic perspective, the logic is understandable. The EU seeks to integrate its neighbourhood more rapidly while limiting the risks associated with future institutional deadlock.
Yet gradual accession does more than offer a pragmatic solution to the EU’s enlargement dilemma. By allowing participation to precede full membership, it begins to redefine the relationship between integration, representation and political equality on which previous rounds of enlargement were built.
The idea of differentiated participation is not new. Scholars including Frank Schimmelfennig, Dirk Leuffen and Berthold Rittberger have long examined forms of differentiated integration, variable geometry and multi-speed Europe. More recently, Schimmelfennig has argued that differentiated membership could reconcile the EU’s geopolitical need to enlarge with its commitment to liberal-democratic standards.
Historically, however, differentiation largely concerned existing member states. What distinguishes the current moment is that differentiation is increasingly moving into the accession process itself.
The traditional enlargement bargain rested on the promise that countries that adopted EU rules would eventually obtain equal political status within the Union. Gradual accession weakens this historical linkage. Participation may increasingly precede representation, and integration may advance faster than political equality.
Accession is a continuum: countries may become deeply integrated into European governance while remaining only partially represented within it
Instead of a clear transition from candidate to member, accession begins to resemble a continuum. Countries may become deeply integrated into European governance while remaining only partially represented within it.
This may appear to be a technical adjustment. In practice, however, it separates participation from equality and reshapes the meaning of membership.
The Western Balkan countries have become the testing ground for this emerging approach.
Albania embodies the promise and the contradictions of gradual accession. Earlier access to EU programmes, markets and funding could accelerate economic convergence, strengthen reforms and enhance the credibility of the accession process. For countries that have spent decades waiting at the Union’s doorstep, these benefits are significant.
At the same time, gradual integration creates new political expectations. The deeper a candidate country participates in European governance, the stronger the demand for political representation becomes.
This dilemma is not unique to Albania. It applies equally to other Western Balkan states, as well as to Ukraine and Moldova.
The future of enlargement depends on which of three trajectories emerges.
In the first scenario, gradual accession serves as a transitional mechanism. Candidate countries progressively integrate before eventually obtaining full membership and equal political rights. Differentiation functions as a bridge rather than a destination.
In the second scenario, gradual accession evolves into a permanent architecture of differentiated membership, creating multiple layers of participation and influence. The long-discussed vision of a Europe organised through concentric circles becomes institutional reality.
The third scenario is more problematic. Candidate countries receive access to programmes, funding and selected policies without a credible pathway to equal membership. Gradual accession risks becoming a substitute for enlargement rather than a route towards it.
The question is no longer whether gradual integration should lead to differentiated membership, but whether differentiated membership may produce differentiated forms of political belonging
The debate is therefore shifting. Earlier discussions focused on whether gradual integration should lead to differentiated membership. The emerging question is whether differentiated membership may ultimately produce differentiated forms of political belonging within the European Union itself.
Enlargement is increasingly about redefining the boundaries of membership. The emergence of frameworks such as the European Political Community suggests that Europe is already experimenting with intermediate forms of political belonging that blur the traditional distinction between insiders and outsiders.
The central challenge is no longer simply who joins the European Union, but what kind of political community the Union is becoming through enlargement. Whether future enlargements preserve political equality among members or give rise to more differentiated forms of belonging may ultimately determine whether the European Union remains a community of equals or evolves into a polity organised around differentiated forms of participation and membership.
