What is the relationship between security policies and democratic debate, oversight and rights? Does coping with security threats require exceptions to the rule of law and reductions of liberties? The inquiry that follows tries to answer such questions in the context of the European Union and takes the case of biometric identification, an area were security considerations and the possible impact on fundamental rights and the rule of law are at stake. Some hypotheses are explored through the case study: “securitisation” and “democratisation” are in tension but some hybrid strategies can emerge; the plurality of “authoritative actors” influences policy frames and outcomes; and knowledge is a key asset in defining these authoritative actors. A counter-intuitive conclusion is presented, namely that biometrics, which seems prima facie an excellent candidate for technocratic decision-making, sheltered from democratic debate and accountability – is characterised by debate by a plurality of actors. Such pluralism is limited to those actors who have the resources – including knowledge – that allow for inclusion in policy making at EU level, but is nevertheless significant in shaping policy; it explains the central role of the metaphor of balancing security and democracy, as well as the “competitive cooperation” between new and more consolidated policy areas. The EU is facing another difficult challenge in the attempt at establishing itself as a new security actor and as a supranational democratic polity: important choices are at stake to assure that citizens’ security is pursued on the basis of the rule of law, respect of fundamental rights and democratic accountability.