Montenegro’s EU Accession at Risk as Croatia Demands Settlement of Bilateral Disputes

For Brussels, the standoff revives an enduring structural headache. For Montenegro, it exposes the fragile internal politics of a candidate state trying to align with European institutions while burdened by the lingering enmities of the 1990s.

A Catalogue of Unresolved Grievances

Zagreb’s demands cover a precise mix of material, legal, and symbolic issues. At the center of the dispute is the legacy of the Yugoslav army’s siege of Dubrovnik in 1991, during which Croatian civilians and military prisoners were held and mistreated at the Morinj detention camp in Montenegro.

Croatia is demanding direct financial compensation for surviving camp detainees, renewed efforts to track down 14 Croatian citizens who remain missing from the war, and the systematic prosecution of unaddressed war crimes.

Beyond wartime accountability, the list extends into territorial assets and local memory politics. A central issue remains the permanent demarcation of the maritime boundary at the Prevlaka Peninsula, controlling access to the Bay of Kotor, which is currently governed only by a provisional agreement reached in 2002. At the same time, Croatian families continue to push for the settlement of long-stalled real estate claims regarding property in Montenegro that was seized or never restored. Further complicating matters is the dispute over the Jadran, a historic 1933 sailing vessel home-ported in Split before the war, which was docked in Tivat when Yugoslavia disintegrated and remains in Montenegrin hands. Finally, symbolic friction persists over the preservation of a memorial plaque at the former Morinj camp alongside the renaming of a public swimming pool in Kotor currently named after Zoran Gopčević, a former camp guard.

In isolation, several of these issues appear manageable through standard bilateral commissions. Together, they represent a high-stakes diplomatic obstacle that Podgorica cannot easily dismantle without triggering severe domestic blowback.

Technical Alignment Meets Unanimous Politics

For years, the European Commission’s expansion framework was understood primarily as an administrative exercise. Candidate nations adopted the 150,000 pages of the acquis communautaire, reformed their judiciaries, adjusted economic regulators, and waited for the green light from Brussels.

That procedural model has increasingly given way to political conditioning. Because every major step in the accession pipeline requires unanimous approval from all current member states, individual capitals hold total leverage over candidates.

Croatia’s stance is anchored in the official Negotiating Framework for Montenegro, which explicitly states that good-neighborly relations and the resolution of bilateral conflicts are mandatory pre-conditions for entry. The European Union has long maintained that it will not import unresolved border or territorial quarrels into the bloc. By invoking this principle, Zagreb frames its demands not as a national obstruction, but as the strict enforcement of established EU standards.

This leverage puts Prime Minister Milojko Spajić’s administration in Podgorica in a precarious position. To satisfy Zagreb, the government in Podgorica must make concessions on historical narratives that parts of its own parliamentary majority strongly reject. Pro-Serbian and pro-Russian political factions within Montenegro’s coalition resist accepting historical responsibility for the 1990s conflict, viewing concessions to Zagreb as a capitulation.

Yet refusing Croatia’s terms guarantees an institutional standstill, freezing Montenegro’s candidate status just as it approaches the finish line.

The Broadening Accession Veto

The dynamic playing out between Zagreb and Podgorica is part of a broader pattern across South-Eastern Europe. The enlargement process has repeatedly transformed into an arena for settling historical accounts.

Slovenia previously used border disputes in the Piran Bay to stall Croatia’s own EU entry talks for years. More recently, Bulgaria invoked identity, language, and minority disputes to block North Macedonia from opening formal negotiations.

In the traditional EU accession model, technical reforms, judicial alignment, and economic integration were presumed to lead directly to membership entry. Under current operational realities, that path is interrupted by individual member states exercising their bilateral veto power to demand the settlement of historical, border, and property claims before entry can be approved.

For existing member states, the accession window represents their absolute peak of political leverage. Once a candidate state enters the Union, its neighbours lose their primary mechanism to force concessions on border disputes or historical compensation. Zagreb is well aware that its bargaining power vanishes the moment Montenegro takes its seat in the European Council.

Conversely, for capitals that remain skeptical of bringing new members into the bloc, bilateral disputes serve a useful purpose. European governments hesitant about enlargement can allow regional disputes to stall candidate nations without having to exercise a direct, controversial veto in Brussels themselves.

Regional civil society networks, including projects backed by the Open Society Foundations – Western Balkans, have attempted to establish alternative mediation channels to prevent these historical disputes from grinding Western Balkan integration to a complete halt. But non-governmental diplomacy struggles to compete with national electoral politics.

Strategic Dilemmas in Podgorica

As 2026 progresses, the diplomatic clock is running against Montenegro. Zagreb’s insistence that dialogue resume immediately leaves little room for delay.

If Podgorica agrees to settle the maritime boundary near Prevlaka, return the Jadran, and rename public infrastructure in Kotor, Spajić risks destabilizing his political coalition at home. If he resists, Montenegro risks losing its status as the regional pacesetter, signaling to the rest of the Western Balkans that procedural compliance with Brussels offers no guarantee of progress.

The dispute exposes the central paradox of current EU expansion policy. While Brussels repeatedly emphasizes the strategic urgency of bringing the Western Balkans into the European fold to counter foreign influence, the mechanics of entry remain tightly held by individual capitals focused on local history.