The European Union should not let the progress of Montenegro and Albania towards membership overshadow unresolved political and reform challenges elsewhere in the Western Balkans, the European Council on Foreign Relations (ECFR) said in a report.

The report, published by former Serbian government official Milica Delević, comes ahead of an expected European Commission enlargement package on Sept. 30, which is due to inform discussions by EU leaders in October. It argues that Montenegro and Albania have emerged as frontrunners but that focusing on countries facing the fewest obstacles risks weakening the bloc's wider strategy for the region.

Montenegro has opened all 33 negotiating chapters and provisionally closed 16, while Albania provisionally closed three more chapters in July, according to the European Commission.

"Focusing on the countries facing fewest obstacles to accession might suit the geopolitical needs of the moment, but it risks losing sight of the original regional dimension of Western Balkans enlargement," Delević wrote.

The EU's original approach was designed not only to prepare countries for membership but also to promote regional cooperation and stability after the wars of the 1990s. The Commission's current Western Balkans framework retains those objectives.

Delević said unresolved issues in Kosovo, Bosnia and Herzegovina and North Macedonia continued to require EU attention. She called for renewed efforts in the Serbia-Kosovo dialogue, reforms in Bosnia and Herzegovina and engagement with EU member states over disputes affecting North Macedonia's accession path.

The report also argues for a more flexible form of gradual integration for countries unlikely to join soon, including greater access to the EU single market in return for reforms.

The Commission already operates a Growth Plan for the Western Balkans that aims to bring parts of the single market and other benefits forward while tying financial support to reforms.

The EU's renewed focus on enlargement followed Russia's full-scale invasion of Ukraine in 2022, which also revived attention to the Western Balkans. Brussels has since described enlargement as a strategic investment in European stability and security. At a June summit, EU leaders said they would continue working with all six Western Balkan partners on reforms and gradual integration into the single market.

Delević said the renewed geopolitical momentum should not come at the expense of the accession process's reform and reconciliation objectives.

"A more ambitious and flexible framework for gradual integration, aiming to include countries in parts of the internal market, would encourage reforms and allow the EU to develop a more intelligent and honest approach to conditionality," she wrote.

The report also warned that weak implementation of rule-of-law and democratic reforms could reduce the transformative effect of the accession process and undermine regional stability.

Montenegro has received particularly strong EU backing this year. In June, the European Commission adopted a financial package setting out the budgetary arrangements for the country once it joins the bloc, describing the step as part of preparations for its eventual accession.

The EU's June Western Balkans summit also said enlargement remained a strategic investment in shared stability, prosperity and security.

Delević argued that successful accession by one or more Western Balkan states could demonstrate that membership remains achievable for countries that implement reforms and align their policies with the EU, but said this should complement rather than replace efforts to address the region's remaining disputes.

"However, neither the EU nor the Western Balkans can ignore the fact that Kosovo is stuck due to unresolved status issues, Bosnia and Herzegovina carries the burden of a dysfunctional constitution imposed by the international community and North Macedonia is held back by bilateral issues with its EU neighbours," she wrote.