A defendant enters a plea to the charges brought by the U.S. attorney at a hearing known as an arraignment. Most defendants — more than 90% — plead guilty rather than go to trial. If a defendant pleads guilty in return for the government agreeing to drop certain charges or to recommend a lenient sentence, the agreement often is called a "plea bargain." If the defendant pleads guilty, the judge may impose a sentence at that time, but more commonly will schedule a hearing to determine the sentence at a later date. In most felony cases the judge waits for the results of a presentence report, prepared by the court's probation office, before imposing sentence.
If the defendant pleads not guilty, the judge will proceed to schedule a trial.
If the verdict is guilty, the judge determines the defendant's sentence according to special federal sentencing guidelines issued by the United States Sentencing Commission. The court's probation office prepares a report for the court that applies the sentencing guidelines to the individual defendant and the crimes for which he or she has been found guilty. During sentencing, the court may consider not only the evidence produced at trial, but all relevant information that may be provided by the pretrial services officer, the U.S. attorney, and the defense attorney. In unusual circumstances, the court may depart from the sentence calculated according to the sentencing guidelines.