Electoral Systems and Government Stability: A Simulation of 2006 Italian Policy Space

Abstract This paper tracks a path from electoral results to government formation, in order to assess whether the characteristics of the party system put forward by the spatial theory of voting may influence, and how, the relationship between electoral system and government stability. In this regard we perform a simulation concerning the 2006 Italian general election, by computing the parliamentary seats that parties would get in an election through various electoral systems, starting from given electors ’ votes. We then introduce two well-known game theoretical models that explain stability and instability of coalition governments. We draw some counterfactual deductions about what would have occurred to Italian government stability if other electoral sys-tems had been in use. The results of our simulation suggest that the stability consequences of technical changes in an electoral system are influenced by the spatial features of the party system