In 1984 Congress passed the Sentencing Reform Act (the "Act")1 in response to the widely held view that defendants who committed similar crimes, under similar circumstances, were receiving grossly disproportionate sentences in federal courts.2 The Act established the Federal Sentencing Commission (the "Commission") to promulgate mandatory sentencing guidelines (the "Guidelines") for federal judges.3 After long debates, the Commission promulgated the Guidelines, which took effect in November 1987.4 For drug and money crimes,5 the Guidelines require a trial judge to make, at sentencing, an independent determination of the amount of contraband involved in the transaction. Additionally, the trial judge must determine whether certain aggravating or mitigating circumstances exist. The Guidelines are silent, however, as to what standard of proof the trial judge should apply in determining the actual amount of drugs or money involved or in determining whether aggravating or mitigating circumstances exist.