Impact of the entrance of a new country into the European Union in the voting power in the Council of the EU

Abstract

[en] Power indexes are key indicators in game theory and allow us to measure the voting power of different agents in a voting system, also called a weighted majority game. If we look at the theory of cooperative games, we can find different indices that try to measure the voting power of the coalitions that can be formed between the various agents or players. In our case, we have focused on the study of the Shapley-Shubik index. The objective of this work is to analyze the impact that the entry of new countries into the European Union would cause on the voting power within the Council of the European Union of the different member states. To do this, we analyzed the variations in the Shalpey-Shubik index of the EU member states as a result of the entry of new countries in four different scenarios.