Introduction

‘Ein Verfassungsgericht!’ This exclamation on the German Verfassungsblog was one of the first responses to the—then only a few hours old—ruling of the Court of Justice of the European Union (CJEU) of April 8, 2014, in which the European Union's data retention directive was invalidated for interfering with the fundamental rights to private life and to the protection of personal data. The great significance of this judgment can scarcely be doubted. The implications for national law are manifold, but perhaps even more gripping is the fact that the CJEU reached such a relentless conclusion in the first place. With the help of clear references to the Charter of Fundamental Rights of the European Union (CFR), the CJEU took its role here as a fundamental rights guarantor very seriously. By invalidating the data retention directive, one could argue, it thereby clearly assumed a constitutional task.

In this regard the judgment, together with the many (academic) responses that followed soon after, forms an interesting illustration of the topic that is central to this chapter, namely the ‘constitutionalisation’ of fundamental rights adjudication at the European level. It brings up a number of highly relevant questions: is what we are witnessing indeed a development of constitutionalisation beyond the state, or at least a constitutional approach to supranational fundamental rights protection? And, to what extent is something similar also visible in the context of the other major European fundamental rights adjudicator, the European Court of Human Rights (ECtHR )?

It is clear that both the CJEU and the ECtHR are (increasingly) important actors in the field of fundamental rights protection. Whereas with the help of the CFR the former is just taking its first steps on the path towards fully-fledged fundamental rights adjudication, the latter for decades now has been more than occupied with eff ectuating the rights laid down in the European Convention on Human Rights (ECHR). For both courts, moreover, it is regularly argued that their practice is taking constitutional shapes. Be it for their far-reaching interpretation of fundamental rights norms, because of the general applicability of certain elaborately carved out standards, or due to the significant effects of a finding of a violation, the constitutionalisation of European fundamental rights adjudication, if anything, seems underway.