“This is not a party”: elements for a sociology of movementism based on the case of La France Insoumise

European political parties are facing a slow erosion of their electoral and activist base. Due to multiple interrelated factors, traditional parties have become increasingly disembedded from society. In an attempt to escape this decline, several political organisations that emerged after the 2008 crisis have taken a movementist turn. These organisations (1) present themselves as “movements” rather than “parties”, (2) provide strategic support to social movements, and (3) explore a way of operating that is intended to contrast with that of traditional parties, and which values freedom of movement. Podemos, the Five Star Movement and La France Insoumise are emblematic of these developments; La République en Marche too, albeit in a slightly different form. This article proposes a novel conceptualisation of movementism, proceeding in two steps. In the first step, drawing on 36 months of research and around a hundred interviews with La France Insoumise, we will show what movementism means for the actors who claim to be part of it, stressing the plurality of meanings attributed to this phenomenon. In the second step, drawing on a comparative approach that sets La France Insoumise into a broader landscape, we will propose an ideal type of the “movementist party”—one capable of opening up a new field of inquiry for political scientists and sociologists.