Based on the premise that a society’s sense of commonality depends upon media practices, this study examines how Hollywood responded to the crisis of democracy during the Second World War by creating a new genre—the war　film. Developing an affective theory of genre cinema, the study’s focus on the sense of commonality offers a new characterization of the relationship between politics and poetics. It shows how the diverse ramifications of genre poetics can be explored as a network of experiental modalities that make history graspable as a continuous process of delineating the limits of community.