Introduction

The protection of human rights is a central task of many modern judiciaries. Judicial review may thereby be limited to the review of the executive; yet in its expansive form, it includes the judicial review of legislative acts. The European Union follows this second tradition. Fundamental rights thus set substantive – judicial – limits to all governmental powers and processes within the Union. They indeed constitute one of the most popular grounds of review in actions challenging the validity of European Union law.

What are the sources of human rights in the Union legal order? Despite the absence of a ‘bill of rights’ in the original Treaties, three sources for EU fundamental rights were subsequently developed. The European Court first began distilling fundamental rights from the constitutional traditions of the Member States. This unwritten bill of rights was inspired and informed by a second bill of rights: the European Convention on Human Rights. This external bill of rights was, decades later, matched by a written bill of rights specifically drafted for the European Union: the Charter of Fundamental Rights.

These three sources of EU fundamental rights are now expressly referred to – in reverse order – in Article 6 of the Treaty on European Union. The provision reads:

This chapter investigates each of the Union's three bills of rights and the constitutional principles that govern them. Section 1 starts with the discovery of an ‘unwritten’ bill of rights in the form of general principles of European law. Section 2 analyses the Union's own ‘written’ bill of rights: the EU Charter of Fundamental Rights.