For many, the enactment of the European Union’s Treaty of Lisbon, with its range of significant human rights provisions, marks the EU’s coming of age as a human rights actor. The Lisbon Treaty inaugurated the legally binding character of the EU Charter of Fundamental Rights (EU Charter), enshrined a commitment to accede to the European Convention on Human Rights (ECHR), and, in Article 2 of the Treaty on European Union (TEU), identified human rights as a foundational value. These changes have already drawn comment as developments that “will change the face of the Union fundamentally,” that take the protection of rights in the EU “to a new level,” and that indicate that “the arguments for improving the status of human rights in EU law… have finally been heard. There is general agreement, in other words, that the EU has reached the high point of its engagement with human rights.

Will international law colonize the last bastion of sovereign discretion? As a matter of traditional doctrine, international law has had little to say about the citizenship practices of states and the terms on which states determine the boundaries of their memberships. Through much of the Westphalian era, states have been essentially unconstrained with respect to who gets citizenship and on what terms. Historically, citizenship status has been considered a matter of national self-definition, jealously insulated more as a matter of reflex than justification. Nationality has been equated with identity, in most cases coinciding with ethnic, religious, or other sociocultural community markers, which, in turn, have more or less mapped onto territorial spaces.