Abstract: A longstanding and influential view in U.S. correctional policy is that "nothing works" when it comes to rehabilitating incarcerated individuals. We re-examine this hypothesis by studying an innovative law-enforcement-led program recently launched in the county jail of Flint, Michigan: Inmate Growth Naturally and Intentionally Through Education (IGNITE). We develop a new instrumental variable approach to estimate the effects of IGNITE exposure, leveraging quasi-random court delays that cause individuals to spend more time in jail both before and after the program's launch. We find that IGNITE exposure dramatically reduces both within-jail misconduct and post-release recidivism. Qualitative evidence suggests a cultural change within the jail as a key mechanism.