Whether the Sentencing Commission acted within its expressly delegated authority by permitting district courts to consider a nonretroactive change in law in determining 'extraordinary and compelling reasons' for sentence reduction

Congress empowered district courts to reduce sentences of federal prisoners for “extraordinary and compelling reasons.” Congress did not define the terms “extraordinary and compelling” but instead expressly delegated to the United States Sentencing Commission the authority to describe what types of circumstances qualify. Exercising that authority, the Sentencing Commission adopted a provision, Section 1B1.13(b)(6), that permits district courts to consider a sentence reduction where, among other things, the defendant has served at least ten years of an unusually long sentence and a nonretroactive change in law produces a “gross disparity” between that sentence and the one likely to be imposed at the time of the motion. The Courts of Appeals are divided on the question presented here: Whether the Sentencing Commission acted within its expressly delegated authority by permit ting district courts to consider , in narrowly cabined circumstances, a nonretroactive change in law in determining whether “extraordinary and compelling reason s” warrant a sentence reduction.