Before the reforms, judges could impose sentences as they saw fit, within a general statutory framework that included only wide-ranging guidelines for maximum and minimum sentences for given crimes. In 1984, the United States Sentencing Commission was established, with the mission to ensure certainty and fairness. It produced guidelines which went into effect in 1987 and have been the subject of criticism. By the end of the decade, sentences were determined on a numeric scale, and judges' influence diminished. Judges' assessment of individual offender corrigibility, and family and social factors--formerly crucial to the sentencing process--hardly mattered anymore. This article includes discussions of the guidelines and their impact on caseload, empirical data, and an analysis. Empirical data show that under the guidelines, trials for drug and firearms crimes have become much more common, and trials for other crimes less common. Analysis raises the question of whether the guidelines provide sufficient incentive for guilty defendants to plead guilty, or whether they encourage innocent defendants to go to trial rather than plead guilty. 2 figures, 18 tables, and 122 footnotes