Most students of politics are familiar with Carl Schmitt’s definition of politics as a friend-enemy distinction. Yet, only few know of alternative conceptions of politics in interwar Germany that emphasize cooperation and legality over confrontation and decisionism. To unlock such views, this article examines the work of Hermann Heller, a social-democratic constitutional theorist, and takes a close look at his conceptualization of politics as a sphere, activity and discipline. For Heller, ‘the political’ consists in turning human conflict into social cooperation. For him, the political may be conflictual, but is also conditioned by shared norms and agreed rules. By consequence, to act politically means to order the antagonistic social relations that are typical of every human society. In this sense, politics is a purposeful activity, but one which leaves the content of every decision unconfined and the potentialities that follow endless. Like politicians, politics scholars must reflect on ethical and legal principles, while remaining focused on context-specific political problems. The study of politics cannot be disconnected from the study of law, ethics and social reality. Heller’s work showed that the way we conceive of politics is directly related to the way we study politics and vice-versa.