This paper aims to stress the relevance of judicial trust in international courts by focusing on the national judges’ trust in the Court of Justice of the European Union (CJEU). Scholars of European Judicial Politics have put a great deal of effort into explaining how the mechanism of preliminary references boosted cooperation among national courts and the CJEU, contributing to the legal integration and constitutionalization of the EU legal order. These studies have pointed to the relevance of legal and political institutional factors in explaining why national courts cooperate (or not) with the CJEU. Nevertheless, there is still the absence of ideas on the development of trust as a functional principle that may encourage cooperation between national and international courts. Using original data collected through surveys, this article explores the nature, causes, and potentials of judicial trust for the functioning of supranational legal orders like the EU. It presents a theory, which links the trust of the national judges to their beliefs about the competence of the CJEU to provide offer a clear guidance on European Union law.
