A federal judge criticized Attorney General Eric Holder for directing prosecutors to pursue shorter prison sentences for drug crimes before new guidelines for sentencing had been approved.

The U.S. Sentencing Commission approved the reduced sentences for federal drug trafficking offenses on Thursday. Holder endorsed the move last month, and the Justice Department instructed prosecutors not to object if defendants sought the newly-proposed guidelines during sentencing.

The Justice Department’s eagerness to apply more lenient sentencing before it had been approved through the appropriate channels frustrated commission member Judge William H. Pryor Jr., despite his support for the reform.

“I regret that, before we voted on the amendment, the Attorney General instructed Assistant United States Attorneys across the Nation not to object to defense requests to apply the proposed amendment in sentencing proceedings going forward,” he said Thursday.

“That unprecedented instruction disrespected our statutory role, ‘as an independent commission in the judicial branch,’ to establish sentencing policies and practices under the Sentencing Reform Act of 1984… and the role of Congress, as the legislative branch, to decide whether to revise, modify, or disapprove our proposed amendment…We do not discharge our statutory duty until we vote on a proposed amendment, and Congress, by law, has until November 1 to decide whether our proposed amendment should become effective.”

“The law provides the Executive no authority to establish national sentencing policies based on speculation about how we and Congress might vote on a proposed amendment,” Pryor’s continued.

“I appreciate the Attorney General’s personal appearance before the Commission last month and his helpful comments in support of this amendment, but I hope that we can avoid, in the future, the kind of improper instruction that he sent federal prosecutors before we voted on the amendment.”

Despite Pryor’s misgivings, the commission’s vote Thursday was good news for Holder.

“This action by the U.S. Sentencing Commission represents a milestone in our effort to reshape the criminal justice system’s approach to dealing with drug offenders,” he said in a statement calling on Congress to legislation that would help reduce the prison population.