I first compare the deliberative  to the liberal and the republican models of democracy, and consider possible references to empirical research. Then I examine what empirical evidence there is for the assumption that political deliberation develops a truth-tracking potential. The main parts of the paper serve to dispel prima facie doubts about the empirical content and the applicability of the communication model of deliberative politics. Moreover, it highlights two critical conditions: mediated political communication in the public sphere can facilitate deliberative legitimation processes in complex societies only if a self-regulating media system gains independence from its social environments and if anonymous audiences grant feedback between an informed elite discourse and a responsive civil society. [The translation of this text, from German to French, is published in two parts. The introduction and sections I, II, and III are published in Participations 2012 (3); the second part will be published in Participations 2013 (1)].