In testimony prepared for a House hearing Thursday, Mukasey indicates a willingness to go along with new sentencing guidelines that reduce federal prison time for crack cocaine convicts - but only for first-time, nonviolent offenders.
New U.S. Sentencing Commission rules taking effect in less than a month would let nearly 20,000 federal inmates seek reductions in their crack cocaine sentences.
It's unclear, if not unlikely, that Congress would act before the rules take effect.
Mukasey, who is to testify before the House Judiciary Committee, said releasing all the inmates eligible under the Sentencing Commission's guidelines could increase violent crime in communities and clog up courts.
The Justice Department estimates that two-thirds of federal inmates serving time for crack cocaine also have violent criminal histories or gun charges in their pasts.
"We think it is imperative for Congress to pass legislation to address the Sentencing Commission's decision," Mukasey wrote to the House committee.
"I emphasize that we are not asking this committee to prolong the sentences of those offenders who pose the least threat to their communities, such as first-time, nonviolent offenders," Mukasey wrote.
The Sentencing Commission's guidelines kick in March 3. About 1,600 federal inmates could be eligible for immediate release.
The commission, which sets federal sentencing guidelines that help judges mete out prison time, voted unanimously in December to let crack cocaine convicts seek the retroactive reductions. The commission acted to ease the disparity between comparatively harsher prison sentences for crack violations than for powder cocaine.
Four of every five crack defendants are black. Most powder cocaine convictions involve whites.
If Congress blocks the new guidelines for all but the nonviolent first offenders, Mukasey repeated past Justice Department pledges to consider "changes to the current statutory differential between crack and powder cocaine offenses."
A commission spokesman did not immediately return a call seeking comment Wednesday, and a House Judiciary Committee official did not have an immediate response.
Mary Price, vice president of sentencing reform organization Families Against Mandatory Minimums, said the Justice Department still will have the ability to make a case against any of the inmates who are seeking reduced sentences. She called Mukasey's 11th-hour appeal to Congress "a little startling."
"This is not the right approach," Price said. "The Justice Department should do its job if they consider somebody who's not appropriate for release."