A Priori versus Empirical Voting Power in the EU Council of Ministers

Numerous scholarly articles have investigated member states’ a priori voting power in past, present and possible future Councils of the European Union (EU). This article introduces three empirically oriented variants of the standardized Banzhaf index and compares them with the standardized Banzhaf index itself. The comparison suggests that the averages of the empirically oriented indices converge towards the Banzhaf index, and hence that there is no dominant ordering of the member states or the issues and, consequently, no stable minimal winning coalitions over time. However, statistical analysis reveals that the country-bycountry average difference from the Banzhaf index, considering all issues, remains significant in all three variants of empirical power.