Over the last decade, there have been remarkable reforms in criminal legal policy and practice in Cook County, Illinois. In this project, I evaluate these changes in terms of their impact on the enduring problem of mass incarceration. First, I consider how prosecutors handle the influx of misdemeanor arrests from so-called broken windows policing. Analyzing 2016 jail data using competing risk models, I predict half of Black public order defendants to be released on dropped charges after spending two weeks in jail. From this, I argue that police and prosecutors use pretrial detention as an unregulated tool of racial control. Next, I evaluate the decarcerative impact of felony charging reform. In December 2016, newly-elected State's Attorney Kim Foxx more than halved the number of felony retail thefts charged in Cook County in less than a month. Using a decade's worth of courtroom event data, I build a regression discontinuity design to quantify how this intervention changed outcomes across the criminal process. On one hand, I find evidence that increased leniency did cause a slight month-to-month increase in crime. On the other hand, though, I find evidence of reduced levels of pretrial detention. I also find that prosecutors maintain pre-intervention drop rates despite handling fewer cases. Overall, I argue that the clear decarcerative benefits of felony charging reform outweigh the slight month-on-month post-intervention increase in retail theft. The third and final chapter evaluates a January 2018 law defining sentences for illegal gun possession. This new act bifurcates subpopulations based on their criminal history: those with no history may be offered probation, while those with multiple convictions face harsher prison terms. This reform intensified a pre-intervention upward trend in the use of probationary sanctions for first-time gun possession. The length of probationary terms also increased while the length of prison terms decreased. That said, these analyses also revealed a notable discontinuity in Summer 2016 caused by an internal policy change that increased the plea bargaining discretion of courtroom prosecutors. As with legislative reforms, this new organizational policy increased the length of probationary sentences for first-time offenders while decreasing the predicted length of prison terms for both groups.