Transnational Judicial Dialogue and Evolving Jurisprudence in the Process of European Legal Integration

European legal integration can be envisioned as containing two dimensions of legal integration: vertical and horizontal. Vertical legal integration is a top down process where the establishment of a hierarchical legal order of courts and laws causes national courts to make more similar decisions over time as they increasingly come under the formal authority of a higher court. The European legal integration literature speaks mainly to vertical, formal, legal integration where the ECJ and EU law have asserted themselves as a formal authority over the national courts of the member states and compel the integration of the national courts. Horizontal legal integration involves national courts making more similar decisions over time because the national courts interact, borrow, and imitate each other informally. Vertical legal integration can compel national courts to take into account EU law and ECJ precedent, but it cannot control for variances in interpretation. The focus of this paper is not just on how the power dynamics of courts and laws have changed in Europe, but also how the legal realm of Europe has shifted to a greater frequency of shared legal outcomes. There have been hints in the European integration literature about horizontal legal integration in many vertical integration studies (See Jupille and Caporaso 2009; Burley and Mattli 1993; Mattli and Slaughter 1995). This paper will pursue further the notion that there are distinct dynamics of horizontal and informal legal integration and that horizontal legal integration in conjunction with vertical legal integration can contribute to a more complete understanding of the process of European legal integration. In this paper I argue that the historical progression of increasingly autonomous and powerful national courts (court empowerment) in Western Europe has allowed a process of transnational judicial dialogue to occur. Transnational judicial dialogue is composed of horizontal, transnational interactions between national high courts judges, where judges across countries voluntarily draw upon each other‟s rulings, logics, and academic writings and incorporate them into their own logics and rulings. I argue that this process of transnational judicial dialogue has furthered legal integration through the transmission of jurisprudence and legal concepts between different member state national judiciaries through informal, horizontal legal integration