Winners and Losers Under Various Dual Majority Rules for the EU Council of Ministers

This Paper studies some of the many options facing EU leaders when choosing a viable voting system for the EU25+. It provides quantitative estimates of the efficiency and power distributions of the various EU voting schemes that are being considered. It also provides intuition on how various aspects of voting rules affect decision-making efficiency and the implied power distribution. The paper also argues that the two big mistakes the EU has made with respect to voting reform were both due to last-minute ‘surprise’ schemes. This time around, EU leaders should limit themselves to choosing among voting systems that have been thoroughly studied and discussed, if they want to avoid a third mistake on this issue.