The aim of this article is to analyse the judicial activism of international courts. More precisely what is, and how should we study judicial activism at the international level? Based on a least-likely case study of the Court of Justice of the EU’s (CJEU) rulings with regard to the EU’s defence procurement policy, we argue that only a combination of legal and political science approaches allow to understand the degree of judicial activism of a court. We will see that the Court has indeed limited the member states capacity to refer to article 346 TFEU which aims to protect the member states’ essential security interests in order to avoid the EU’s public procurement rules. The analysis of two rulings more specifically - Commission vs. Italy (2008) and Instiimi Oy (2012) - shows that the Court’s legal reasoning has proven audacious. However, we argue that this is only moderate activism. In adopting a strategic constructivist approach, the paper contributes to the more recent literature which stresses that the Court’s influence can only be understood in embedding the analysis of its rulings in the broader political and institutional context of European integration (Martinsen 2015).