Must a court, when taking due account of the rule of prejudicial error on review of agency action, comport with Chenery?

QUESTION PRESENTED Congress requires that, when a court finds error in a Department of Veterans Affairs (“VA”) action, the court must “take due account of the rule of prejudicial error.” 38 U.S.C. § 7261(b)(2); see 5 U.S.C. § 706 (requiring the same for review of other federal agencies’ actions). The provision’s purpose is to avoid rendering courts “impregnable citadels of technicality.” Shinseki v. Sanders, 556 U.S. 396, 407, 129 S. Ct. 1696, 1705, 173 L. Ed. 2d 532 (2009). It is not to unwind Chenery. Nor can it be. Chenery reflects and enforces a requirement of the U.S. Constitution. In particular, for a delegee of Congress’s Article I legislative power to invoke that power validly, the delegee must state the basis for doing so. Chenery requires the delegee’s reasons to be those contemporaneous to the action. The Court, to be sure, has never clarified that Chenery’s foundation is the Constitution rather than a statutory requirement or prudential concern. A circuit split has resulted on this important issue. In the decision below, the Federal Circuit forbade all per se rules that deem prejudicial any kind of VA error whatsoever. The error subjugates Chenery to a mere statute, thrusting VA’s overseeing courts into upholding agency error on precisely the post hoc rationalization that Chenery prohibits. Chenery’s constitutional nature requires the opposite result. The question presented is: Must a court, when taking due account of the rule of prejudicial error on review of agency action, comport with Chenery?