Political polarization is often argued to be a major threat to democracy. This article examines whether the two different forms of polarization, ideological and affective, may risk some of the core assumptions of democratic legitimacy. The paper argues that ideological polarization is linked with increasingly radical ideological positions being accepted as legitimate contributions to democratic processes, which may lead to the erosion of the democratic culture of society. Affective polarization, in turn, presents a risk to the type of political collaboration that characterizes legitimate democratic processes. The article presents some remarks on how these forms of polarization could be pre-emptively addressed in education: first, by demonstrating to students the practical consequences of neglecting the core democratic principles of toleration (Forst) and reciprocity (Rawls) in society; and second, through forms of political action that engage students' political emotions in support of democratic principles and way of life in a nonpartisan way.