The impact of enlargement on the balance of power in the Council

Författare: Ehin Piret

How will the EU’s decision-making processes be affected if the number of member states grows significantly? This issue has been discussed since enlargement once again became a priority for the EU. In this analysis, Piret Ehin (University of Tartu) assesses the effects of three enlargement scenarios on the balance of power in the Council. (2025:5epa)

The Council is one of the EU’s main decision-making bodies and primarily uses qualified majority voting (QMV): a proposal is adopted if 55 percent of member states, representing at least 65 percent of the total EU population, vote in favour. How would future EU enlargements impact on the weight of different member state groupings in the Council?

In this European Policy Analysis, Piret Ehin, Professor at the University of Tartu, highlights the complexities and potential shifts in power dynamics within the EU Council after prospective enlargements. As the timing and scope of further enlargement remain uncertain and depend on various factors, she considers three enlargement scenarios which would significantly alter the balance of power in the Council: the accession of Ukraine, Moldova, and Georgia (EU30), the accession of the six Western Balkan countries (EU33), and the accession of both these groups (EU36). The main findings could be summarized as follows:

  • Founding members, large states, eurozone members, Mediterranean, and post-communist states would retain the ability to block Council decisions under all three enlargement scenarios.

  • Small states would need partnerships with more populous countries to meet QMV requirements, while large countries would need the support of many smaller states to pass legislation.

  • Post-communist countries would gain the ability to block decisions under all three enlargement scenarios.

  • The weight of Northern European countries would decrease, while the power of Southern member states would increase.

  • Enlargement would reduce the weight of Eurozone members in the Council, but they would still meet QMV requirements under all scenarios.

According to the author, past enlargements have generally improved the EU’s decision-making capacities by promoting treaty reforms and other changes that have made processes more efficient. Future enlargements would increase the pressure to abandon unanimity in the Council, especially in foreign and security policy matters. However, the author argues, meaningful reform of Council decision-making depends on large states offering incentives to smaller ones, such as adjusting the conditions for meeting qualified majority, introducing supermajority requirements, or enabling differentiated integration.