Does the Lisbon Treaty improve decision making in the Council of Ministers? : Analysis based on the Veto Player Theory and the Banzhaf Power Index

European Union (EU) decision making is decisively shaped by the formal voting rules in place. Especially the Qualified Majority Voting (QMV) rules in the Council of Ministers (CM) can be seen as crucial determinants for the capacity to act and the efficiency of the EU as a whole. The Lisbon Treaty, which has recently come into force, brings along renewed alterations to these voting rules. Since the Treaty of Nice, QMV rules were often criticized for causing gridlock in the EU and while the issue of inequitable voting power always accompanies the introduction of new QMV rules, this thesis intends to analyze whether the new QMV rules may bring about any improvements with regard to these two points. The analysis using the Veto Player Theory and the Voting Power Approach comes to the conclusion that improvement with regard to gridlock in the CM has been achieved under the Lisbon Treaty, while at the same time increasing inequity of a priori voting power to the advantage of large and very small Member States.