The Primacy of EU Law: new controversies about its scope and limits

The lecture revisited the primacy of EU law. First proclaimed by the Court of Justice more than 60 years ago, in the Costa v ENEL judgment, primacy has a simple core meaning, namely that national courts must make EU law prevail over national law in the case of conflict. The practical consequences of that simple rule have developed over the years, and the presentation will critically discuss some recent developments regarding the scope of primacy, as understood by the Court of Justice, and will also discuss the recent cases of resistance against the full acceptance of primacy by the national (constitutional) courts of some EU states. This resistance culminated in the infringement action Commission v Poland, leading to the Court of Justice’s judgment of 18 December 2025.