From social movements to institutionalization: The Five-star Movement and the high-speed train line in Val di Susa

The article is dedicated to the analysis of the events of 2019 concerning the realization of the high-speed railway line linking Turin and Lyon (Treno ad alta velocità, Tav), an infrastructure project that has always been a crucial issue for the Movimento 5 stelle (Five-star Movement, M5s). Given the importance of environmental issues to the M5s, the party has always paid considerable attention to the Tav issue, and it supported the movement against the construction of the railway (the ‘No Tav’ Movement, Mnt). Over time, the M5s became the only political actor at national level willing to champion the ‘No Tav’ cause. Nevertheless, it ended up as part of a government that gave the final go-ahead to the project. The aim of this article is to consider the Tav question as a litmus test of the evolution and transformation of the M5s from a protest movement into a party of government. The first section discusses the relationship between the M5s and the ‘No Tav’ Movement, and the reasons for the proximity between the two. In the second section, we consider the changes that took place within the M5s, when it entered government. In the third section, we trace the most significant events of 2019 concerning the Tav. Finally, we show how the Tav issue has been one of a number of ‘reality tests’ which the Movement has had to face during its time in government, and discuss its relevance for the literature on new parties and populist parties in government.