Bringing Europe’s Margins into the Union: Enlargement in an Age of Frozen Conflicts

By Matthew Parish, Associate Editor

Friday 24 July 2026

The European Union has long defined itself as a peace project. It emerged from the ruins of the Second World War upon the deceptively simple premise that economic integration would make armed conflict between its members not merely undesirable but practically impossible. Enlargement has therefore never been solely an exercise in economics or bureaucracy. It has always been a geopolitical instrument, extending the zone within which disputes are settled by law rather than force. Yet today that ambition confronts perhaps its greatest obstacle since the end of the Cold War: the proliferation of frozen conflicts along Europe’s periphery. From Transnistria in Moldova to Abkhazia and South Ossetia in Georgia, from Kosovo to the unresolved division of Cyprus, and above all to the territories occupied by Russia in Ukraine, unresolved territorial disputes have become barriers not merely to peace but to European integration itself.

These conflicts differ in origin, legal status and intensity. Some are the legacy of Yugoslavia’s violent dissolution. Others emerged from the collapse of the Soviet Union. Some involve internationally recognised states; others involve entities recognised by almost nobody. Nevertheless, they share one defining characteristic: they remain unresolved because powerful actors benefit from their continued ambiguity. Frozen conflicts are rarely accidents of history. They are often carefully maintained instruments of political leverage.

For the European Union this creates an uncomfortable dilemma. The Union has traditionally been reluctant to admit states whose borders are disputed or whose territory is not fully under governmental control. The reasoning is understandable. Membership carries obligations of mutual solidarity. It also extends the Union’s external frontier. Importing unresolved territorial disputes into the EU risks transforming local disagreements into continental crises.

Yet insisting upon complete territorial resolution before accession creates precisely the incentive external powers seek to exploit. If a hostile state can permanently prevent a neighbour’s European integration simply by occupying a fragment of its territory, then aggression becomes an extraordinarily effective instrument of strategic policy. Russia has demonstrated this logic repeatedly over the last three decades.

The consequence is that enlargement policy risks becoming hostage to precisely those who oppose enlargement.

This suggests that the European Union requires a more sophisticated constitutional approach to accession.

One possibility would be the explicit recognition that EU membership applies only to territory under the effective control of the applicant government at the date of accession, without prejudicing the state’s legal claims to occupied territory. Such an arrangement would separate questions of sovereignty from questions of administration. The applicant state would continue to assert its internationally recognised borders, while the practical operation of EU law would extend only to areas under governmental control.

There is already precedent for differentiated territorial application within European law. Cyprus joined the European Union in 2004 despite the continuing division of the island. EU law is suspended in the northern part of Cyprus pending a political settlement. Although the Cypriot case is unique, it demonstrates that absolute territorial control has never been an immutable constitutional requirement.

A similar model could be developed for future enlargements.

Ukraine, Moldova and Georgia each present variations on this challenge. None would require identical solutions, yet each could potentially accede while temporarily excluding territories under foreign military occupation or separatist administration from the application of EU law. Such arrangements would not legitimise occupation. On the contrary, they would reinforce the principle that occupation cannot determine the constitutional future of an internationally recognised state.

Critics argue that admitting states with unresolved conflicts risks drawing the European Union into future wars. That concern deserves careful consideration. However, legal drafting can distinguish between the defence of territory actually participating in Union institutions and territories remaining under unlawful occupation. Mutual assistance clauses need not automatically apply in identical ways to territories outside the effective jurisdiction of the member state. Such legal precision would inevitably be politically controversial, but European integration has always depended upon innovative constitutional compromise.

The larger question concerns the purpose of enlargement itself. If enlargement is merely a reward for countries that have already achieved stability, then frozen conflicts become permanent barriers. If, however, enlargement is understood as an instrument for creating stability, then waiting indefinitely for perfect conditions becomes self-defeating.

The Western Balkans illustrate the urgency of this debate. Bosnia and Herzegovina remains constrained by constitutional structures established at Dayton nearly three decades ago. Kosovo’s status continues to divide European capitals. Serbia balances between Brussels and other geopolitical partners while insisting upon positions incompatible with rapid accession. North Macedonia endured years of delay over issues of national identity and historical interpretation before negotiations even began. Albania has likewise experienced prolonged waiting despite extensive reforms. Every year of uncertainty weakens confidence that the European perspective remains genuine.

The same applies further east. Moldova has undertaken reforms at remarkable speed despite extraordinary economic and security pressures. Georgia’s European aspirations remain substantial despite domestic political turbulence. Ukraine has demonstrated a level of institutional resilience few observers predicted before 2022. To tell these societies that accession must await comprehensive settlement of conflicts largely maintained by external coercion risks undermining precisely the pro-European political forces the Union seeks to encourage.

None of this implies abandoning rigorous accession criteria. Judicial independence, anti-corruption reforms, democratic accountability, protection of minorities, economic convergence and administrative competence remain essential. Membership cannot become a geopolitical gift divorced from constitutional standards. But territorial perfection should no longer function as an absolute veto where international law clearly attributes responsibility for the dispute to external aggression or prolonged occupation.

Such an approach would also strengthen the credibility of international law. Too often international legal principles appear aspirational rather than operational. If unlawful occupation prevents European integration indefinitely, then international law rewards the occupier rather than the victim. By contrast, allowing accession notwithstanding unresolved occupation would demonstrate that aggression cannot dictate constitutional outcomes.

Ultimately the European Union must decide whether it remains fundamentally a political union or merely an economic club. Political unions necessarily confront imperfect realities.

The history of European integration has always involved gradual accommodation of complex constitutional arrangements, transitional provisions and carefully negotiated exceptions. Frozen conflicts represent another such challenge requiring creativity rather than paralysis.

Europe’s margins are no longer peripheral to European security. They have become its front line. The states lying between the European Union and an increasingly revisionist Russia have repeatedly demonstrated their commitment to European values, often at immense human cost. If the Union cannot devise constitutional mechanisms capable of incorporating them despite unresolved conflicts created or sustained by external powers, it risks allowing those powers an enduring veto over Europe’s future.

The enlargement debate should therefore be reframed. The central question is not whether frozen conflicts exist, but whether those conflicts should be permitted to determine the political destiny of sovereign European nations. If the answer is no, then the European Union must develop accession mechanisms that uphold international law, preserve collective security and deny aggressors the strategic rewards they seek. Such an evolution would not weaken the European project. It would reaffirm its founding purpose: replacing the politics of coercion with the rule of law, and extending the continent’s zone of peace not by waiting for history to become uncomplicated, but by shaping history through institutions capable of accommodating complexity.