ALICE M. BATCHELDER, Circuit Judge. In this consolidated appeal, we REVERSE the judgment of the district court in Bricker and AFFIRM the judgments in McHenry and Orta. This appeal concerns three federal prisoners serving lengthy sentences. Invoking the compassionate-release statute, 18 U.S.C. § 3582(c)(1)(A), which allows a court to reduce a final prison sentence for “extraordinary and compelling reasons,” each prisoner sought release based on a recently enacted “policy statement,” U.S.S.G. § 1B1.13(b)(6). In that statement, the Sentencing Commission announced that a nonretroactive change in the law can present an “extraordinary and compelling” reason warranting a sentence reduction if (1) a prisoner has served at least 10 years (2) of “an unusually long sentence,” (3) there is a “gross disparity” between the actual sentence being served and a hypothetical sentence that would apply under the current law if any nonretroactive changes in the law since the original sentencing were given retroactive effect, and (4) the sentencing court has fully considered “the defendant’s individualized circumstances.”1 To cut to the heart of this, because some recent revisions to federal sentencing law are not retroactive, old inmates are serving prison sentences that are much longer than the sentences of new inmates who committed the exact same crimes. Recognizing the unfairness, the Commission decided that the disparity was a good reason to grant these old-timers early release, or was at least a factor worth considering when deciding whether an individual old-timer had an “extraordinary and compelling reason” for early release. That is understandable and even laudable. The question is whether the Commission has the authority to do that under the law, particularly the Constitution. To be specific, the questions in this appeal concern the separation of powers, specifically the Commission’s power to overrule a Circuit Court’s interpretation of a statute or to promulgate a policy statement that contradicts other federal statutes. The Sentencing Commission “is a peculiar institution”—a judicial-branch agency with “quasi-legislative” power—about which the Supreme Court has acknowledged that its “unique composition and responsibilities . . . give rise to serious concerns about a disruption of the appropriate balance of governmental power among the coordinate Branches.” Mistretta v. United States, 488 U.S. 361, 383-85 (1989). Based on the analysis that follows, we conclude that the Commission overstepped its authority and issued a policy statement that is plainly unreasonable under the statute and in conflict with the separation of powers. We therefore hold that U.S.S.G. § 1B1.13(b)(6) is invalid.