Party Switching in the Italian Chamber of Deputies, 1996–2001

Almost one-fourth of the members of the lower house in Italy, the Chamber of Deputies, switched parties at least once between 1996 and 2001. Why would a legislator abandon one party and enter another during a legislative term? Starting from the basic assumption that politicians are ambitious, we examine electoral and partisan motivations for members of parliament (MPs) who switch parties. We conclude that party switching most likely is motivated by party labels that provide little information about policy goals and that pit copartisans against each other in the effort to serve constituent needs. Switching is especially frequent when ambitious politicians operate under heightened uncertainty.