May 2025.

In this commentary published by Carnegie Europe in May 2025, Stefan Lehne examines the challenges facing the European Union’s enlargement policy in a context marked by a geopolitical contest with Russia but also, in a different way, with the United States. While enlargement has historically been a process based primarily on reforms and the gradual integration of candidate countries, it has now become a central element of geopolitical contest.

It highlights that the European Union faces priorities that are sometimes in conflict with one another. On the one hand, some member states wish to maintain an approach based on reforms and the progress made by candidate countries, particularly in the Western Balkans. On the other hand, the war in Ukraine is pushing the EU to view enlargement as a potent tool for security and stability. Discussions about gradual accession or intermediate forms of integration reflect this desire to adapt the process to new geopolitical challenges.

This publication argues that enlargement remains the most powerful instrument that the EU has at its disposal to strengthen the continent’s stability, security and unity. In the face of Russian attempts at interference, internal dynamics and the rise of transactionalism, it calls for stronger European engagement, a differentiated approach tailored to each candidate country and increased capacity for innovation in managing the accession process.

You can find the commentary “EU Enlargement in the Age of Geopolitics” by Stefan Lehne and published by Carnegie Europe here.