To establish 'clear and unmistakable error' based on legal error, must a veteran show that there was an error of law at the time of the challenged decision which undebatably altered the outcome of the benefits decision, or must a veteran also show that the meaning of the law itself was undebatable?

In the uniquely pro -claimant veteransbenefits system, Congress has provided that an otherwisefinal agency decision is subject to revision if that decision was based on “clear and unmistakable error,” or “CUE.” Regulations and longstanding agency practice dictate that CUE is “the kind of error, of fact or of law, that when called to the attention of later reviewers compels the conclusion, to which reasona-ble minds could not differ, that the result would have been manifestly different but for the error.” 38 C.F.R. § § 3.105(a)(1)(i), 20.1403(a), (c). And, as this Court confirmed in George v. McDonough , 596 U.S. 740 (2022), the error must be based on the law that applied at the time of the original decision, not a lat-er change in law or interpretation. In the decision below, the Federal Circuit misread George to require more. It held that a CUE claimant must show not only that a legal error had a clear effect on the outcome of a benefits decision , but also that the law itself was undebatably clear at the time of the prior decision. The question presented is: To establish “clear and unmistakable error” based on legal error , must a veteran show that there was an error of law at the time of the challenged decision which undebatably altered the outcome of the benefits decision, as the regulatory text provides, or must a veteran also show that the meaning of the law itself was undebatable, as the Federal Circuit held?