Choosing Not to Join: Citizens’ Explanations for Party Non-Membership

Political parties are the central actors in representative democracies to recruit new politicians and voice citizens’ demands in politics. To execute these functions, party members are crucial. Moreover, party members have got more influential over the years in parties’ decision-making. However, party membership has long been, and continues to be, an activity of a minority. For example, in the Netherlands, only around 3% of the electorate is a party member. While existing research has examined why citizens join political parties, far less is known about why the majority of citizens chooses not to. Existing explanations of party membership build on incentive-based models, which emphasize process-related motivations such as the desire to meet like-minded individuals or to express ideological commitments. However, these frameworks cannot explain non-membership. The absence of membership cannot simply be understood as the inverse of joining: citizens may refrain from joining for reasons that are not captured by these incentive models, such as disengagement, distrust, perceived barriers or a sense that parties are not responsive or inclusive. Understanding citizens’ reasons for party non-membership is nevertheless crucial. Most political parties continue to rely on members for their organizational survival, internal democracy, and societal embeddedness. If party membership increasingly reflects the preferences and capacities of a small group of the electorate, this raises broader questions about representation, inclusiveness, and the legitimacy of parties. This paper, therefore, shifts the focus from why citizens join political parties to why citizens do not join political parties. Using data from the 2025 Dutch Leiden Election Study, we distinguish between current party members, former members, non-members who have considered membership, and non-members who have never considered joining a party. Depending on their response, respondents were asked an open-ended follow-up question about their reasons for leaving a party, deciding not to join despite having considered it, or never joining at all. This design allows us to distinguish between different forms of party non-membership and to analyze citizens’ own explanations for both non-entry and exit. Additionally, we examine whether these motivations differ across groups that are structurally underrepresented in (party) politics: young people, women, practically educated citizens, and individuals with a migration background. By systematically mapping citizens’ own explanations for party non-membership, this study could potentially extent the incentive-based models of party participation and contribute to debates on party inclusivity and organizational survival.