Duverger's Laws: Between social and institutional determinism

Abstract. The purpose of this article is to relocate Duverger's Laws within the debate about the effects of electoral systems on the number of parties. Although Duverger's theory has always been seen as the best example of a purely institutionalist approach to the issue, it is possible to argue that this is only true if one overemphasises the meaning of the laws without considering Duverger's justification and explanations for them. However, if one takes into consideration not only the laws, but also Duverger's theories about the effects of electoral systems on the number of parties as a whole, one can argue that his theses do not have a purely institutionalist character and can therefore coexist with theories that try to take into account variables other than electoral rules.