Mediated contestation comprises all forms of political opponents’ mutual engagement that are represented in mediated public communication and/or for which mediated public communication is directly used by the conflicting parties. Liberal, republican, deliberative and agonistic theories of democracy agree that the extent, structure and style of mediated contestation all have important consequences for democracy, albeit on different grounds. We summarize the normative views of mediated contestation espoused in these strands of democratic theory and show how they evaluate a central contemporary trend in mediated contestation, the increasing polarization of the citizen audience. Agonistic and liberal theories of democracy generally welcome, whereas deliberative and republican theories generally disfavor increasing audience polarization. Diverging from the other theory strands in this regard, deliberative democratic theory is shown to be ambivalent about different facets of the phenomenon, despite its overall skepticism.