The EU did not only extend its prerogatives, but also more and more countries have joined. Membership has grown from the original six founding states to the present 27 sovereign member states. In addition, there are now four official candidate countries, Croatia, Iceland, Macedonia and Turkey. There are approximately half a billion citizens in the Union (USA 310 million), and its GDP is roughly $16 trillion (USA $14 trillion). We study the relationship between the member states in Union. The EU is a supranational organization; the decision process is therefore affected by national interests. We present a dataset of votes cast by member countries over EU proposals and put forward a novel method to measure the dependency between voting behavior of countries.
The Council of the European Union (Council of Ministers, Council or Consilium) is the principal decision making institution of the Union. In fact, it can be seen as the daily executive branch of the European Union with the European Commission as the executive. The Council acts give a description of the positions of Member States on the legislative proposals made by the European Commission. Based on these positions, we calculate Spearman rank correlation coefficients between the Member States. These correlations give insights in the position of countries in European decision making. These correlations can also be used to determine the support the position of a member state gets in the Council. The positions of a country with low correlations, like the UK, thus get little support in the Council, despite the fact that the UK has a large voting weight. When voting weights and the coherence in voting behavior are both taken into account, then it follows that the positions of Lithuania, Netherlands, Germany and Sweden get most support. One of the implications of the Treaty of Lisbon is the expansion of qualified majority voting by having it replace unanimity; another change is the change in the voting weights. These voting weights were previously set in the Treaty of Nice, which implied a more obvious overrepresentation of the small member states in comparison with the Treaty of Lisbon. We use the correlations as predictors of future voting behavior and subsequently look at the question whether these changes in voting weights have a significant effect on the support the position of member states get in the Council. We find that these changes only significantly affect (increase) the support of the positions of Germany and France.