Although agencies are the dominant force in criminal law today, existing scholarship has largely failed to analyze how these bodies perform as agencies. We know little about how the institutional design of these agencies affects their output or whether the politics of regulation are different when an agency is responsible for the regulation of criminal justice issues as opposed to traditional regulatory areas. This Article takes up that task by evaluating the agencies charged with regulating one of the most important aspects of criminal law: sentencing. Many reformers turned to agencies to regulate sentencing because they did not trust the political process on its own to produce rational sentencing policy in a tough-on-crime culture. This Article explores what kind of model works for regulating criminal sentences if the goal is to create an influential agency that can temper rash political impulses. Drawing from administrative law, political science, and the actual experience of state and federal commissions, the Article demonstrates that—contrary to conventional wisdom—the agency model can succeed. But, unlike other substantive areas where an independent agency is seen as the most effective, an insulated agency model is not a viable answer when the agency is responsible for regulating criminal sentencing. Instead, agencies responsible for sentencing are more efficacious when they are politically enmeshed and operate largely like interest groups. Like an interest group, a well-connected agency that can produce politically salable information is more likely to wield influence than one that is aloof from political pressures.