The terrorist event is not only a military action but also a communicative action, as Lenin theorised in the epoch of the so-called "agit-prop" (social agitation and political propaganda). In the contemporary epoch, dominated by the media character of the public sphere, that means a change in the relationship between terrorist action and information. At the time of the Moro case, Marshall McLuhan recommended press silence so as to deprive the Red Brigade of their main objective: visibility. Palestinian terrorism raised the aim of its own propagandist strategy in 1972, when the media event of the year (the Munich Olympics) became the site of an action live on world television. With the kamikaze action against the World Trade Center in New York, this dialectical between terrorism and the public media sphere reaches its theoretical apex: the twenty minutes distance between the first and the second impacts against the Twin Towers was calculated for the time required so that the second event could be transmitted in live world television without censorship. The struggle for visibility in the global arena paradoxically makes the non coincidence between media system and modernity visible. Understanding the "dialogic" character of the terrorist action means understanding that the answer can not be only a military reaction, but must look for new communicative forms of action.