The Effect of Turkey’s EU Membership on the Voting Power within the Scope of the Treaty of Lisbon in the Council of the European Union

Enlargement is one of the most important issue for European Union. The situation that makes this issue important is the influence of membership of the candidate states on the voting power distribution. In this study, the impact of membership of Turkey on voting power distribution is evaluated according to the acts adopted by Council of the European Union and voting system brought by the Treaty of Lisbon. In the analysis, voting power distribution of the countries’ is taken into consideration in the case of voting independent from each other and Banzhaf power index is used for voting power measurement. Based on the results of the voting power analysis, in the case of countries’ voting independent from each other populous countries loss power and others gain power with the accession of Turkey. When the Council does not act on a proposal from the Commision or the High Representative of the Union for Foreign Affairs and Security Policy, all member countries loss power.