Legitimacy Under Constraint: Geopolitics, Transformation and Contestation in EU Enlargement

Debates about the democratic legitimacy of EU enlargement have intensified, yet scholarly approaches remain fragmented: some equate legitimacy with formal authorisation (referenda, ratification, compliance), while others invoke diffuse notions of fairness, ownership or credibility. This paper offers a conceptually coherent way of capturing this complexity by defining democratic legitimacy in enlargement as the publicly justified rightfulness of authority claims, articulated through accepted procedures, accountable practices and contestable interpretations. Rather than assessing whether enlargement is legitimate, the article examines how legitimacy is constructed, invoked and challenged by different actors over the course of the accession process. We propose a framework that conceptualises enlargement as a multi-arena process of negotiation and transformation accompanied by legitimacy construction, where governments, EU institutions, civil society, stakeholders and citizens mobilise different logics of justification and legitimation. To ensure analytic precision, the empirical section focuses on two arenas where legitimacy claims are both most visible and most politically consequential: (1) enlargement as a set of choices embedded in geopolitical and security dynamics, where decisions are often influenced by urgent security threats; and (2) enlargement as domestic political and socio-economic transformation, where distributive conflicts and unequal adjustment costs generate competing claims about fairness and accountability. These two arenas illuminate some of the key tensions identified in the current enlargement round: geopolitical imperatives vs democratic reforms, and economic winners vs losers. They also reveal why legitimacy cannot be understood as consensus or inclusiveness, since enlargement inevitably produces trade-offs that no procedural design can fully neutralise. Drawing on document analysis, parliamentary debates and civil society reports across two contrasting enlargement contexts (to be specified), the article traces how different actors mobilise, contest and reconcile legitimacy claims within and across these arenas. The analysis shows that legitimacy is not a single evaluative verdict but a dynamic configuration of justificatory practices whose relative weight shifts with geopolitical shocks, domestic politics and EU-level institutional constraints. The article contributes to debates on democratic legitimacy in multi-level governance settings by offering a framework that is empirically grounded yet conceptually parsimonious. It clarifies the sources and limits of legitimate authority in enlargement and explains why some accession processes sustain public and elite support while others face recurring legitimacy crises.