Summary

How political parties organize directly affects who is represented and which policies are prioritized. Political parties structure political choice, which is one of the main functions generally ascribed to them. Their roles as gatekeepers for policies and political careers are closely linked to their nature as membership-based organizations, and to the extent to which they empower members to influence these crucial choices directly or indirectly. Parties also play a crucial role as campaign organizations, whose organizational strength influences their electoral success. The literature often summarizes differences in how parties organize and campaign by identifying major party types, which can be regarded as “classic models” of party organization. Yet, actual parties must adapt to changing environments or risk being supplanted by newer parties or by other political actors. For instance, in recent years one popular adaptation has involved parties opening their decision-making processes by introducing party-wide ballots to settle important questions. Changes like these alter how parties act as intermediaries in representation and political participation. Thanks to the increasing availability of comparable data on party organizations in established and new democracies, and in parliamentary and presidential systems, today’s scholars are better equipped to study the origins and impacts of parties’ organizational differences.