Despite their centrality to modern democracy, until recently political parties were relegated to the margins of normative democratic theory, taking a back seat to social movements, civil society associations, deliberative experiments, spaces for local participatory government, and direct popular participation. Yet, in the past 15 years, a burgeoning literature has emerged in democratic theory focused directly on parties and partisanship; that is our focus in this review. We locate three main normative defenses of parties: one centered in the special role parties can play in political justification as agents of public reason, a second that looks to the way parties contribute to deliberation, and a third that focuses on the partisan commitment to regulated political rivalry and peaceful rotation in office. In this last connection, we survey work on the constitutional status of parties and reasons for banning parties. We then consider the relation of partisanship to citizenship, and in a fourth section we turn to the ethics of partisanship. Parties and partisanship are interwoven but separable: If partisans are necessary to realize the value of parties, the reverse holds as well, and parties are necessary to realize the value of partisanship.