Which harmless error standard applies to a habeas corpus challenge under 28 U.S.C. §2255?

QUESTION PRESENTED This court has never decided which harmless error standard applies to a habeas corpus challenge under 28 U.S.C. §2255. Some courts have used the Chapman standard which puts the burden on the government to show that the error was “harmless beyond a reasonable doubt.” Chapman v. California, 386 U.S. 18, 24 (1967). Most courts have used the less strict, more Brecht standard, also used in §2254 cases, which asks whether the error had a “substantial and injurious effect” on the jury’s verdict. Brecht v. Abrahamson, 507 USS. 619, 622 (1993). Nevertheless, in just March of this year, one court of appeals wrote: To date the Supreme Court has not addressed whether Chapman, Brecht, or a third standard applies to federal prisoners seeking post-conviction relief under 28 U.S.C. §2255. Neither has our court taken a position on the issue and indeed “our caselaw gestures in conflicting directions.” Ruiz v. United States, 990 F.3d 1025, 1031 (7th Cir. 2021) (citation omitted). Petitioner Munyenyezi stands convicted of federal crimes despite her jury not having been instructed on an essential element of the crimes charged. The correct instruction was not given because the case requiring it, Maslenjak v. United States, 137 S.Ct. 1918 (2017), was not decided until after Munyenyezi’s conviction and appeal were final. When the district court denied Munyenyezi’s §2255 claim, she appealed. Although the district court had used the Chapman standard, the First Circuit Court of Appeals rejected that standard and applied a version of the more lenient Brecht test. The First Circuit applied that deferential test even though Munyenyezi’s claim had not been, and could not have been, heard previously. This ii court should grant Munyenyezi’s petition, address the important unresolved issue of how to measure harmless error under §2255, and then hold that the correct standard in this context is whether the error was “harmless beyond a reasonable doubt,” as set forth in Chapman. The Question Presented is: When reviewing a habeas corpus claim under 28 U.S.C. §2255, where the court is considering for the first time whether an erroneous jury instruction on an essential element was harmless, does the court apply the Chapman “harmless beyond a reasonable doubt” standard, the “substantial and injurious effect” Brecht standard, or some other measure of harmless error? iti