Bilateral baggage slows Montenegro’s path to EU membership

Croatia has moved to slow Montenegro’s march toward the European Union, making it clear that outstanding historical and territorial disputes must be addressed before negotiations conclude. Officials in Zagreb are pressing Podgorica to settle long-standing grievances spanning war crimes prosecution, wartime compensation, and unresolved border delimitations before giving their blessing to finalize the membership process.

Montenegro has often been billed as the front-runner in the Western Balkans enlargement race, but Croatia’s stance serves as a reminder that accession is never purely an administrative exercise. Zagreb's intervention ties Montenegro's closing of negotiating chapters—the policy areas an aspiring state must align with EU rules—to resolving thorny regional legacies left unresolved since the conflicts of the 1990s.

For ordinary citizens across both countries, unresolved borders and wartime claims remain sensitive domestic issues that routinely spill into national politics. For Montenegro, the intervention is a practical roadblock. Accession is not simply a technical checklist ticked off in an office in Brussels; it is the passport to the EU single market, freedom of movement, and access to cohesion funding.

Yet for candidate countries, the process often comes down to geography: any existing member state holds the power to pause an applicant’s European ambitions. By bringing unresolved wartime compensation and border lines to the negotiating table, Zagreb is employing standard institutional leverage to ensure its bilateral priorities are settled before Podgorica gains equal voting rights at the Council table.

Inside the Brussels bubble, enlargement operates under a principle of absolute consensus. Every single step of the journey—from opening an initial negotiating cluster to closing individual policy chapters and ratifying an accession treaty—requires the unanimous approval of all 27 member states.

While the European Commission evaluates accession through technical benchmarks and legal alignment, national capitals hold the ultimate veto. It is an unwritten tradition of EU expansion that existing members use this structural leverage to settle lingering bilateral disputes with their neighbors before the door swings shut. The institutional machinery in Brussels prides itself on objective merit, yet in the Council of the European Union, a single member state’s historic grievance carries exactly the same weight as thousands of pages of adopted community law.

Podgorica will have to engage directly with Zagreb if it wants to keep its accession timetable on track. Diplomats from both capitals are expected to conduct bilateral talks to seek mutually acceptable ground on border demarcation and legal processing of war-era compensation claims.

Until Zagreb is satisfied with the progress, Montenegro's bid to formally close its accession chapters will remain held up in Council working groups. The Commission may attempt to mediate behind closed doors, but enlargement rules dictate that unless Croatia lifts its objections, Montenegro's accession talks cannot reach the finish line.