The important changes that have taken place in the European Union as a result of the latest enlargements have made it necessary to redesign decision-making procedures again and again. This has contributed to a renewal of interest in issues related to the choice and design of dichotomous voting procedures in recent years, to a conspicuous increase in the number of academic papers, both theoretical and applied, related in one way or another to these issues and to heated debates within the scientific community. As a result of this 'fever’ there have been various movements within this community that have gone beyond the academic realm, including press articles and explicit attempts to influence politicians or their advisers on the choice of voting rule for the EU Council of Ministers. At the basis of some of these recommendations is what is called, perhaps a little ostentatiously, ‘a priori voting power theory’. The main purpose of this book is to provide a critical revision of the foundations of this theory and of the recommendations that stem from it, based on more than ten years of joint research on the subject.

Prior to this collaboration, the first author of this book was preparing her Ph.D. One of the chapters of her thesis sets out the application to the EU Council of the two-stage model of the decision-making process in committees of representatives. This model assumes that each representative follows the will of the majority in his/her constituency on every issue.