Frogs,mice and mixed electoral institutions: party discipline in Italy's XIV Chamber of Deputies1

Through the analysis of nearly 5,700 electronic votes cast by members of the Italian lower house, this article focuses on the electoral incentives shaping legislative behaviour in assemblies elected under mixed electoral rules. The study finds that the incentives indirectly engendered by the interaction between the majoritarian and proportional components of the Italian mixed system strengthen party discipline, which is high for every legislator type regardless of mandate and specialisation. Legislators elected in single-member districts are equally, if not more, susceptible to pressures to stick to the party line as their colleagues elected from a party list. Moreover, indicators of ‘electoral path’, like relative seat safety and dual candidacy, matter to party discipline more than simple seat type.