The principle of effectiveness of EU law: a difficult concept in legal scholarship

Effectiveness is a principle frequently used by the Court of Justice of the European Union to secure the authority of EU law over national law. This study analysis the scholarly treatment of the concept in most relevant selected academic literature and draws some conclusions, mostly that difficulties remain surrounding the conceptualization of the principle. The Court uses it in a variety of ways and judicial outcomes are linked to the context of every case at hand. On one hand, we find effectiveness as a stand-alone principle or expression of general "effet utile"; but, on the other hand, we see the use of the term strongly connected to the effective judicial protection of individual rights and/or as limit to national procedural autonomy. The concept is furthermore embedded in a complex matrix of various other principles of EU law, namely primacy, direct effect, indirect effect or the obligation of consistent interpretation, and Member State liability for breaches of EU law. The results of the study lead to question whether there is really one single concept of effectiveness in EU law and lead to further research in order to explore whether a comprehensive and coherent theory is necessary, feasible and/or desirable.