Carlos Maldonado-Vargas v. United States

Whether harmless error review under Federal Rule of Criminal Procedure 52(a) requires the Government to show that erroneously admitted evidence did not substantially influence the jury’s verdict, or whether an appeals court may affirm a conviction based on the sufficiency of untainted evidence alone. Whether an appellate court errs when it labels “waived” a claim of prejudicial spillover from vacated counts, without inquiring whether the failure to raise that claim in the opening brief was an intentional relinquishment of a known right, where the predicate for the claim first materialized when the government conceded that the counts should be vacated less than two weeks before oral argument and almost two years after the opening brief was filed.