WASHINGTON -- The percentage of minority inmates in US prisons has increased sharply since federal sentencing guidelines took effect 17 years ago, with blacks generally receiving harsher punishments than whites because of mandatory minimum terms for drug-related crimes, a federal advisory panel concludes.
The 15-year study by the US Sentencing Commission, which sets guidelines for federal judges, examines whether the guidelines have brought uniformity to punishments. It found that although sentencing has become ''more certain and predictable," disparities still exist among races and regions of the country.
The findings come as the Supreme Court considers the constitutionality of the guidelines, which advocates say are critical to achieving fairness.
The justices could decide by next week whether to throw out the system because it allows judges, not juries, to consider factors that can add years to sentences.
''The big unanswered question is, do we need to have sentences growing this way," Douglas Berman, an Ohio State University law professor, said yesterday. ''Nobody wants to go back to the bad old days of complete unguided judicial discretion."
Before the guidelines were created in 1987, judges had wide discretion in issuing sentences. The guidelines give judges a range of possible punishments for a given crime and make it difficult for judges to go outside those boundaries.
According to the study released Tuesday, the average prison sentence today is about 50 months, twice what it was when lawmakers began calling for a uniform sentencing system in 1984, due mostly to the elimination of parole for offenses such as drug trafficking.
The percentage of whites in prison dropped sharply from about 60 percent in 1984 to 35 percent in 2002, the report said. It attributed the decrease to a dramatic growth in Hispanics imprisoned on immigration charges.
In addition, the gap between sentences for blacks and whites widened. While blacks and whites received an average sentence of slightly more than two years in 1984, blacks now stay in prison for about six years, compared to about four years for whites.
The report attributed the disparity in part to harsher mandatory minimum sentences that Congress imposed for drug-related crimes such as cocaine possession. In 2002, 81 percent of these offenders were black.
The study found generally harsher punishments in the South compared with the Northeast and West. It concluded that legal differences in the individual cases ''explain the vast majority of variation among judges and regions."
A bigger problem causing sentencing disparities, it said, was plea bargaining. The study said prosecutors offered more lenient punishments than those mandated in the guidelines in as many as one-third of cases, as an incentive for getting guilty pleas.
''There is still work to be done to achieve the ambitious goals of sentencing reform," the report states.