Seat Apportionment by Population and Contribution in European Parliament After Brexit

The problem of apportioning seats to member countries of the European Parliament after Brexit and in view of new accessions/exits is delicate, as countries with strong economies (and their consequent large contributions to the European Union) require that they have greater representative weight in the European Parliament. In this paper, we propose a model for seat apportionment in the European Parliament, which assigns seats taking into account both the percentages of the populations and the percentages of the contributions by each member state to the European Union budget by means of a linear combination of these two quantities. The proposed model is a modification of the approach given by Bertini, Gambarelli, and Stach in 2005. Using the new model, we studied the power position of each European Union member state before and after the exit of the United Kingdom using the Banzhaf power index. A short latest-literature review on this topic is given.