China has established a petition system to elicit information about grievances. However, the petition system may have perverse effects because it also reveals to the center the failure of local-level officials to resolve those grievances. Anecdotal accounts suggest that local officials have incentive to silence petitioners, often with the use of repression. In this article we study whether non-regime threatening petitions would provoke local governments' coercive response. To tackle the endogenous relationship between petition and repression, we take advantage of a natural experiment afforded by a change in hydroelectricity policy in China. In particular, we use provincial hydropower outputs as an instrument to identify citizen petitions. We find that citizen petitions significantly increase a province's spending on its repressive apparatus. The results suggest a paradoxical outcome of China's petition system: while it may help reduce the national authority's use of repression, it has caused an explosion of repression within the authoritarian system as a whole.