Scholars of civil conflict have long recognized the importance of state strength in the suppression of nascent insurgencies. However, previous empirical investigations have generally focused on the material and coercive dimensions of state power, obscuring the critical role played by the generation of widespread voluntary compliance through processes of political communication, that is, the production of “soft power.” In contrast, in this article I focus on a factor—mass communication technology—that can enhance state capacity only by strengthening the state's ability to broadly and publicly disseminate political messages. I argue that the enhanced capacities for large-scale normative influence generated by mass communication technologies can be expected to produce substantial barriers to the mobilization of militarized challenges to state rule, by strengthening economies of scale in the marketplace of ideas. Utilizing newly compiled cross-national data on mass media accessibility in the post–World War II period, I show that densely constituted mass media systems dramatically reduce the probability of large-scale civil violence, thereby providing new evidence for the fundamental importance of nonmaterial state capacities in the suppression of internal armed conflicts.