Comparing the procedures and practice of judicial dialogue in the US and the EU: effects of US unconstitutionality and EU’s preliminary interpretative rulings

The article investigates the role and powers of the Supreme Court of the United States (SCOTUS) and the European Court of Justice (ECJ) when a conflict between 'federal'/EU and State law arises. It focuses on how it is solved and the procedure followed to assess, in particular, what is the added value of the European preliminary ruling procedure (PRP), and what the composite European Union (EU) judicial system can learn from the United States (US) experience and the other way around. While in the EU the PRP is the main test bench for the relationship between ECJ and State courts, such a structured mechanism is lacking in the US, though other avenues of cooperation have been established over the last two centuries. Against this background, the contribution first reviews and compares the effects of a declaration of unconstitutionality in the US with the interpretative preliminary rulings rendered by the ECJ in which incompatibility between EU and national norms is de facto asserted and the duty to disapply arises. Second, it considers, respectively, the power of SCOTUS to remand a case to the State courts, once the State law has been judged unconstitutional, and how disapplication of the national law in contrast with EU law works as a result of an ECJ's ruling. Third, in both systems, it reviews the strategies and the arguments for judicial dialogueused by State courts to react and resist the higher court's assessment. Fourth, it examines proposals to better integrate the views and determination of the State courts into the activity of the 'federal'/EU court and vice versa. In summary, the comparative analysis suggests that SCOTUS tends to prefer a more decentralized approach in enforcing its rulings, largely influenced by its distinct models of judicial review. In contrast, the ECJ appears more inclined to assert substantial control, reserving considerable discretion to dictate the specifics of if, when and how the duty to disapply should come into play