In 2003, the year before its “Big Bang” enlargement, the European Union made a declaration in Thessaloniki: “The future of the Balkans is within the European Union.” In the 20 years since, the EU has not made good on that promise of future membership, nor have leaders in the Western Balkans risen to the occasion.

The all-but-halted integration of the Western Balkans into the European Union has led experts and citizens alike to wonder why the transformative power of the EU, at its peak in 2004 when it admitted ten countries from Central Europe and beyond, has proven ineffectual in this region. The answer is a combination of EU and region-specific factors. The EU failed to put democracy at the centre of its policy towards the Western Balkans as it was able to for the “Big Bang” countries. Twenty years later, poor democratic governance is the main obstacle to the region’s future membership.