We revisit the construct of political polarization and current distinctions between issue-driven and affective polarization. Based on our review of recent research on polarization from psychology, political science, and communication, we propose to treat polarization as a process that integrates the concepts of social identification (collective self-definition) with ideologically opposed camps - that is, psychological groups based on support or opposition to specific socio-political issues and policies (related to issue-driven polarization), and that of ideological and psychological distancing between groups (related to affective polarization). Furthermore, we discuss the foundations of polarizing groups - and more specifically, the role of...