The Time Path of Legislative Party Switching and the Dynamics of Political Competition: The Italian Case (1996–2011)

Abstract

Political competition is more realistically described as a dynamic process rather than as a series of static stages in which parties compete over policy and government formation. This paper focuses on legislative party switching as the main manifestation of this endogenously evolving process, linking individual switching behaviour to policy and office incentives that are assumed to evolve throughout the life of the entire legislature. Using a new data set tracking the timing of MPs’ changes in party affiliations between 1996 and 2011 in Italy, it is found that switching is mainly motivated by policy reasons and that it is more likely during government formation periods and budget negotiations. These results are a consequence of the interplay between MPs’ ambition and the alternation of key phases in the legislative cycle.