If a defendant is found guilty at trial or pleads guilty, the court will set a date for sentencing—in the federal system usually a month or two after the verdict or plea. As a technical matter, no judgment of conviction has been entered until a sentence is imposed.
Traditionally, sentencing has been considered a matter allocated principally to the discretion of the judge. Under a regime known as indeterminate sentencing, the judge could impose any sentence from zero to the maximum set by the legislature for the crime, without any meaningful appellate review. This led to a perceived problem of disparate sentencing, under which different judges might give wildly different sentences for comparable cases, a problem exacerbated by the absence of any need for a judge to explain or justify the sentence, and the absence of appellate review. In the 1980s, the federal Congress and a number of states introduced measures designed to structure sentencing to make the process more coherent and diminish—or at least channel—the discretion left to trial judges.