My paper will analyse the mechanisms by which power is exercised at a transnational scale in internal security matters by analysing the overall development of the different data bases in police and migration matters and the projects to expand them. What are the groups in charge and their relations. How far the specialists of technology (EULISA) have an impact on framing the channels of communication between police organisations? How far security is seen as provided through technological solutions? I will analyse in details what are the logics at stake in terms of interoperability at the EU level, the way the system is constructed and its goals, including its relation to freedom, data protection, privacy. The paper will assess in conclusion the contemporary situation regarding the practices of collaboration, and the justifications given to these collaborations between EU members and between EU and third countries at the transatlantic level
