Although scholarly consensus suggests that dissent causes repression, the behaviors are endogenous: governments and dissidents act in expectation of each other’s behavior. Empirical studies have not accounted well for this endogeneity. We argue that preventive aspects of repression meaningfully affect the relationship between observed dissent and repression. When governments use preventive repression, the best response to dissent that does occur is unclear; observed dissent does not meaningfully predict responsive repression. By contrast, governments that do not engage in ex ante repression will be more likely to do it ex post. We follow U.S. voting scholarship and propose a new instrument to model the endogeneity: rainfall. We couple rainfall data in African provinces and U.S. states with data on dissent and repression and find that dissent fails to have a significant effect on responsive repression in states that engage in preventive repression.