Political parties have only recently become a subject of investigation in normative political theory. Parties have traditionally been studied by political scientists in their organizational features and in relation to the analysis of related topics such as party systems and electoral systems. Little attention, however, was paid until recently to the normative assumptions that underlie partisanship and party politics. Are parties desirable for democratic politics? How should liberal democracies deal with extremist and/or anti-democratic parties? Do religious parties undermine the secular...