This paper presents new causal estimates of incarceration’s effect on voting, using administrative data on criminal sentencing and voter turnout. I use the random case assignment process of a major county court system as a source of exogenous variation in the sentencing of misdemeanor cases. Focusing on misdemeanor defendants allows for generalization to a large population, as such cases are very common. Among first-time misdemeanor defendants, I find evidence that receiving a short jail sentence decreases voting in the next election by several percentage points. Results differ starkly by race. White defendants show no demobilization, while Black defendants show substantial turnout decreases due to jail time. Evidence from pre-arrest voter histories suggest that this difference could be due to racial differences in exposure to arrest. These results paint a picture of large-scale, racially-disparate voter demobilization in the wake of incarceration.