This paper examines ongoing changes in the definition and status of party membership in established and new parliamentary democracies. It starts by analyzing data from an 18-country study of contemporary party organization, asking whether ideological positions or party success explain variations in the procedural and financial accessibility of traditional membership, and in the development of alternative forms of party affiliation. It then asks whether there is a link at the aggregate national or party level between the accessibility of party membership and political engagement, looking in particular at on-line interactions and self-reported political participation. The paper concludes with case studies of membership types and membership activity based on party membership surveys.
