Using a hierarchical logistic model, the authors analyzed data on Three Strikes-eligible offenders in California and the counties where they were sentenced. The analysis found that discretion functions as a “safety valve”, preserving some sentencing proportionality, but also allowing political concerns to influence sentencing decisions. The study found that a more conservative political environment was strongly associated with stricter applications of the law. Prosecutorial and judicial discretion benefits offenders unequally. Though the size of the black population had no significant effect, black offenders were more likely to receive Three Strikes sentences, while younger ones were less likely.