European apportionment via the Cambridge Compromise

Seven mathematicians and one political scientist met at the Cambridge Apportionment Meeting in January 2011. They agreed a unanimous recommendation to the European Parliament for its future apportionments between the EUMember States. This is a short factual account of the reasons that led to the Meeting, of its debates and report, and of some of the ensuing Parliamentary debate. 1. Background and Brief 1.1. Background. As the European Union has grown and its population has developed, so has the constitution and structure of the European Parliament. In recognition of the need for an orderly allocation of Parliamentary seats between the EU Member States, its Committee on Contitutional Affairs (AFCO) commissioned a Symposium of Mathematicians to “identify a mathematical formula for the distribution of seats which will be durable, transparent and impartial to politics”. The purposes of the reform were described thus in [3]: ◦ The aim of the symposium is to discuss and, if possible, to propose to the Committee on Constitutional Affairs a mathematical formula for the redistribution of the 751 seats in the European Parliament. The formula should be as transparent as possible and capable of being sustained from one Parliamentary mandate to the next. ◦ The purpose of the Symposium is to eliminate the political bartering which has characterised the distribution of seats so far by enabling a smooth reallocation of seats once every five years which takes account of migration, demographic shifts and the accession of new Member States. Date: Revised August 20, 2011. 2010 Mathematics Subject Classification. 91B12.