The U.S. Sentencing Guidelines restrict judicial discretion in part to reduce unwarranted racial disparities. However, judicial discretion may also mitigate disparities if judges use discretion to offset disparities emanating from prosecutorial discretion or sentencing policies that have a disparate impact. To measure the impact of judicial discretion on racial disparities, we examine doctrinal changes that affected judges' discretion to depart from the Guidelines. We find that racial disparities are either reduced or little changed when the Guidelines are made less binding. Racial disparities increased after recent Supreme Court decisions declared the Guidelines to be advisory; however, we find that this increase is due primarily to the increased relevance of mandatory minimums, which have a disparate impact on minority offenders. Our findings suggest that judicial discretion does not contribute to, and may in fact mitigate, racial disparities in Guidelines sentencing.

Joshua Fischman & Max Schanzenbach, Racial Disparities under the Federal Sentencing Guidelines: The Role of Judicial Discretion and Mandatory Minimums, 9 Journal of Empirical Legal Studies 729–764 (2012).