The concept of trajectory let us reinitialize the dialogue, several times attempted, between semiotics and the long-lasting project of an ethnography of moderns by Bruno Latour, coupled with a socio-anthropological account of the modes of existence that were invented by the moderns and extended in the confrontation with other collectives. Being part of the base conceptual tools, trajectory is one of the most recurrent terms in the final synthesis of the project (Latour 2012), also thanks to the lucky condition of not being immediately associated to any specific tradition within human sciences. Latour actually operated a progressive purification of the lexicon, which led to the disappearance of several terms that were clearly marked by their semiotic origin, that he adopted in previous contributions (actant and enunciation above all). From the first text about the regimes of enunciation (Latour 1999) to the modes of existence, the disappearance of the semiotic vocabulary makes room to terms more closed to the ordinary experience, like trajectory, used in its explicit metaphorical power and related for instance to reseaux (web) and hiatus. After a genealogical reconstruction of the use of trajectory in Latour’s writings, we would like to concentrate on the political mode of existence, one of the first to present trajectory as a relevant concept. “Politics is not some essence, it is something that moves, it is something that has a trajectory.” (Latour 2007, p. 4). The statement is contained in an article reinterpreting De Vries positions: the political speech is hence characterized through its own trajectory, for instance looking to public relevant issues and the way they can reassemble the collective around it. We would like to finally discuss another reading of the political domain, dialoguing also with Luhmann system theory (see also Basso 2012), in the frame of a semiotics of practices, strategies and forms of life (Fontanille 2008). Specific examples of contemporary issues in Italy will be used to give concreteness to the theoretical debate. Bibliographic references Basso Fossali, P., “Il gesto interprete del potere e il politico alla mercé del comico. Piccola introduzione teorica”, E/C, 2010. Fontanille, J., 2008, Pratiques sémiotiques, Paris, PUF. Latour, B., 1999, “Piccola filosofia dell'enunciazione”, in P. Basso, L. Corrain, eds., Eloquio del senso, Genova, Costa&Nolan. Latour, B., 2007, “Turning Around Politics. A Note on Gerard de Vries’ Paper”, Social Studies of Science. Latour, B., 2012, Enquête sur les modes d’existence, Paris, La Découverte.