Strategic Power in the European Union

Abstract

In this paper we propose a new method to evaluate the distribution of power between decision-making bodies in the European Union. Conventional methods that measure the voting power of players, such as the Banzhaf, Johnston, Holler and Shapley-Shubik indices, are insufficient for this purpose. They take no account, in an endogenous way, of the differences in the abilities of players to affect the outcome of decision-making, which are a result of the existence of political institutions. We propose a different way to measure decision-making power based on the distance between a player's ideal point and the equilibrium outcome of a game. While all previous indices are based on cooperative game theory, the index developed in this paper is based on non-cooperative game theory, which has been the dominant thrust of theoretical politics and economics in the last years. The new index is applied to legislative procedures in the European Union.