The construction of party membership

While the collapse of party membership in the last half‐century has consumed much of the focus of party scholarship, the notion of membership itself is surprisingly under‐theorised. This article presents a tripartite framework for understanding party membership as a constructed concept: from the perspective of the state, the individual and the political party. As organisational mediators and strategic electoral actors, political parties construct varying notions of membership in order to mobilise resources and gain legitimacy, while balancing the participatory demands of citizens with the legal and normative expectations imposed by the state. Using a number of illustrative examples from Europe and beyond, the article analyses the development of supporters' networks and the extension of participatory opportunities to non‐members. Designed in part to address this membership decline and to offer individuals a different way of engaging with political parties, these initiatives are seen as a crucial step in the evolution of modern parties towards looser, more individualised and amorphous networks of affiliation.