Political realism points out that politics is to create and sustain a legitimate order in a context of persistent disagreement, with the possible surge of conflicts, and where political power inevitably uses coercion. Political realists contend that modus vivendi is a contingent political arrangement at the level of the political constitution that allows diverse groups of people to coexist peacefully. Proposals of modus vivendi do not say enough about how to manage disagreements and conflicts. In this paper, I argue that proposals of agonistic democracy supply this lack. I contend that agonistic democracy proposals share the premises of political realism and contribute to the sustainment of a liberal modus vivendi.