On Penrose's square-root law and beyond

Abstract

In certain bodies, like the Council of the EU, the member states have a voting weight which depends on the population of the respective state. In this article we ask the question which voting weight guarantees a 'fair' representation of the citizens in the union. The traditional answer, the square-root law by Penrose, is that the weight of a state (more precisely: the voting power) should be proportional to the square-root of the population of this state. The square root law is based on the assumption that the voters in every state cast their vote independently of each other. In this chapter we concentrate on cases where the independence assumption is not valid.