Résumé : The growing influence of social media platforms, and the disinformation that circulates in them, has transformed the public spheres. How to deal with disinformation is an open normative, empirical and political question in contemporary democracies. In this article, we outline an agenda on the institutional strategies pursued in the European Union (EU), the normative understandings of the public sphere that such strategies imply, and the analytical challenges to undertake this line of inquiry. We argue that there is an emerging competition in the EU field of disinformation – constructed by actors coming from different pre-existing fields, such as journalism or foreign policy – not only to define what is ‘true’ from what is ‘fake’, but also to determine the sort of the public sphere and democracy we ought to strive for. This perspective allows us to anticipate which actors might be empowered (or disempowered) depending on how disinformation is addressed in regulatory terms.