Federal criminal sentencing has changed dramatically since 1988. Fifteen years ago, judges determined if and for how long a defendant would go to jail. Since that time, changes in substantive federal criminal statutes, particularly the passage of an array of mandatory minimum penalties and the adoption of the federal sentencing guidelines, have limited significantly judicial sentencing power and have remade federal sentencing and federal criminal practice. The results of these changes are significantly longer federal prison sentences, as was the intent of these reforms, and the emergence of federal prosecutors as the key players in sentencing. Yet, at the same time, average sentence length appears to be falling slowly as judicial tendency ...