The rise of judicial power has been a global trend in the last three decades. Supreme and constitutional courts play an increasingly larger role in defining the direction, shape and content of public policies in many countries. The Nordic supreme courts have not been an exception. They have often taken a firmer stand on constitutional issues, determining the fundamental questions of politics. In some cases, their decisions even provoked accusations of excessive judicial activism. The impact of a constitutional ruling often goes well beyond the cases actually adjudicated by the courts. Therefore, it is of increasing importance to understand how Nordic judges justify their decisions in constitutional cases. The project studies the reasoning-practice of the supreme courts of five Nordic countries: Sweden, Norway, Denmark, Iceland, and Finland. Large comparative constitutional projects rarely include any Nordic country. The aim of this project is to join the global academic discourse on constitutional reasoning and to enrich it with the Nordic countries’ experience. We will identify patterns of argumentation in order to discover common traits and trends. This allows us to make a comparison with other supreme and constitutional courts in the world, in relation to which these studies have already been conducted. The comparison then enables us to better appreciate the constitutional role of judges in the Nordic countries and to inform debates on constitutional reasoning.