Parliamentary democracy is the most common regime type in the contemporary political world, but the quality of governance depends on effective parliamentary oversight and strong political parties. Denmark, Finland, Iceland, Norway, and Sweden have traditionally been strongholds of parliamentary democracy. In recent years, however, critics have suggested that new challenges such as weakened popular attachment, the advent of cartel parties, the judicialization of politics, and European integration have threatened the institutions of parliamentary democracy in the Nordic region. This volume examines these claims and their implications. The authors find that the Nordic states have moved away from their previous resemblance to a Westminster model toward a form of parliamentary democracy with more separation-of-powers features—a Madisonian model. These features are evident both in vertical power relations (e.g., relations with the European Union) and horizontal ones (e.g., increasingly independent courts and central banks). Yet these developments are far from uniform and demonstrate that there may be different responses to the political challenges faced by contemporary Western democracies.