De Mesquita’s scientific contributions

doi:10.1017/S0003055410000274 Istudy how a revolutionary vanguard might use violence to mobilize a mass public. The mechanism is informational—–the vanguard uses violence to manipulate population member’s beliefs about the level of antigovernment sentiment in society. The model has multiple equilibria, one equilibrium in which there may be revolution and another in which there is certain not to be. In the former, structural factors influence expected mobilization, whereas in the latter they do not. Hence, the model is consistent with structural factors influencing the likelihood of revolution in some societies but not others, offering a partial defense of structural accounts from common critiques. The model also challenges standard arguments about the role of revolutionary vanguards. The model is consistent with vanguard violence facilitating mobilization and even sparking spontaneous uprisings. However, it also predicts selection effects—–an active vanguard emerges only in societies that are already coordinated on a participatory equilibrium. Hence, a correlation between vanguard activity and mass mobilization may not constitute evidence for the causal efficacy of vanguards—–be it through creating focal points, providing selective incentives, or communicating information. Imagine a citizen with antiregime feelings who is