The public sphere is a communication arena where speakers discuss political and societal issues, positions, and arguments in order to arrive at solutions for common problems. Normative functions of the public sphere in democracies, such as monitoring and control of politics, deliberation, and public opinion formation, have been extensively debated in the fields of communication and political theory, most frequently against the backdrop of the nation-state. Trends of globalization and global governance, however, go along with transformations of the state, the increasing involvement of transnational institutions, and major changes in media systems.