This paper examines the contribution of German subnational constitutional courts to the judicialization of politics in the German states, known as Länder. This research goal entails three dimensions. First, I have to define and measure judicialization. To accomplish this task, I use an index recently developed by an international group of scholars of comparative politics. Second, based on major theoretical approaches, I identify possible causes that might give reasons for judicialization, namely institutional preconditions and preferences of justices. In a third step, I use a linear regression in order to test the theory empirically and find links between causes and effects of judicial decision-making in subnational constitutional courts. The findings confirm institutionalist approaches that contribute to explaining decision-making in German subnational constitutional courts.
