The Justice Department is adding significantly to the workload for federal prosecutors, telling them they must include far more information in criminal indictments and seek additional indictments in thousands of pending cases to comply with a Supreme Court decision.

The Bush administration is fashioning a legal defense to that ruling, which has led several judges to declare federal sentencing guidelines unconstitutional.

In a memo Friday to federal prosecutors, Deputy Attorney General James Comey spelled out changes to be followed while the government defends the guidelines.

The nearly 20-year-old system of sentencing people convicted in federal court was called into question by the Supreme Court's ruling late last month in a state sentencing case. Justices said only juries, not judges, can decide factors that lengthen prison terms beyond maximums spelled out in state sentencing guidelines.

The ruling also appears to give defendants a right to demand that every factor that could lengthen a sentence be put to a jury and proved beyond reasonable doubt.

Comey said the government does not believe that ruling should apply to federal judges, who often make factual determinations that add years to prison sentences. To be on the safe side, however, he said prosecutors should include aggravating factors in indictments that could add time to prison sentences, to be decided by a jury. Comey said that new indictments should be sought with that information in pending cases.

He also said defendants pleading guilty should sign waivers that agree to let a judge decide their fates.