What kind of party is and has been the Five Star Movement?

During its short life, the Five Star Movement (M5S), the main new populist party of the Italian political system, experienced significant organizational changes, which marked its different phases. We can identify four phases: the gestation (2009-2012), the entry into the parliament (2012-2017); the preparation for the 2018 election, followed by the first government experience (2017-2019), and the current phase, characterized by the transformation into a ‘state-centered’ party, struggling with endless organizational restyling (2019-21). The academic literature linking populism to party organization is still scarce, as scholars have mainly focused on other questions related to populism. This contribution aims at bridging this gap, by investigating the evolution of the M5S’s organizational profile. I follow two different yet interrelated paths. Firstly, I perform a close examination of the party’s official documents: the ‘Non-Statute’ (2009) and the 2012, 2017 and 2021 Statutes. Jointly, I resort to the now-classic distinction of the ‘three faces’ of the party put forward by Katz and Mair (i.e., party on the ground, party central office and party in public office). I investigate who each of the three faces is represented by, during the different phases of the M5S, and what the power relations between the faces are. Thus, I detect whether this populist challenger party has followed the same trend as traditional parties in being dominated by the party in public office, or, on the contrary, it has pursued a different strategy. This research has significant implications for solving the puzzle of the kind of party the M5S is becoming today.