Federalism and Treaty Enforcement in the European Union: Letters from America

Drawing on a comparative analysis of the constitutional framework on treaty enforcement in the
European Union and the United States this paper addresses two suggestions – two Letters from
America – to the European Court of Justice (‘ECJ’), as the EU institution responsible for ensuring
that in the interpretation and application of the EU Treaties the law is observed. First, the paper
recommends that more emphasis be put on the constitutional dimension of the analysis of whether
an EU agreement or a provision thereof is directly applicable. Second, it suggests that a rebuttable
presumption in favour of direct applicability be introduced in the Court’s analysis. Embracing both
suggestions would render more persuasive the ECJ’s approach to the issue of treaty enforcement as
it would increase the predictability of the Court’s analysis and thus legal certainty, while at the same
time carving out a meaningful space for considerations based on domestic constitutional principles,
including those that aim to protect the delicate balance between unity and diversity that characterises
the EU compound polity.