Using data on party lists and parliamentary groups, we outline the network of connections among politicians Italy and apply community-detection algorithms to recover enduring party groups that persist across parties.

Theoretically, political parties are both the elements of governing coalitions as well as coalitions themselves. Parties, even small ones but especially major ones, are made up of several groups. The boundaries of parties are permeable, and parties evolve and change from election to election. These dynamics are present everywhere, but the Italian case is particularly useful to track them, because parties have changed in significant ways while the same politicians continue their careers in those parties. At the same time, the ideological and partisan cleavages in Italian politics are also well developed. There is thus a structure to understand. The Italian case thus represents a very crucial case for an international comparative perspective.

Narratives of party change in Italy tend to identify how new parties are built from those leaving old parties. This project aims to trace empirically such coalitions as revealed by the decisions of politicians to stand for election with a party.