United States v. Marcus
The Supreme Court rejected a rule the Second Circuit had used to review trial mistakes that were never raised at trial, ruling that a conviction shouldn't automatically be thrown out just because there was some remote chance the jury convicted a man based only on conduct that wasn't yet illegal.
The case now goes back to the appeals court to apply the correct four-part legal test for these 'plain error' claims, rather than the looser 'any possibility, however remote' standard it had used.
“a retrial is necessary whenever there is any possibility, no matter how unlikely, that the jury could have convicted based exclusively on pre-enactment conduct.”
Describing the overly broad Second Circuit rule the Court rejected.
How it got here: Marcus was convicted at trial; on appeal, the Second Circuit vacated his conviction using its own plain-error test, and the Government asked the Supreme Court to review that ruling.
The Case in Depth
What happened
Glenn Marcus was charged with forced labor and sex trafficking covering conduct from January 1999 to October 2001, but the federal law he was charged under didn't take effect until October 28, 2000. His trial judge never told the jury it could not convict him based solely on conduct from before that date, and Marcus's lawyer never asked for that instruction or objected at trial.
The question before the Court
If a jury could have convicted someone based only on conduct from before a criminal law existed, does an appeals court have to reverse just because that outcome was possible, even barely?
Why it matters
Federal appeals courts nationwide use 'plain error' review to decide whether to overturn convictions when a defendant's lawyer failed to object at trial. This ruling clarifies that courts can't reverse convictions just because a small, remote risk of an unfair conviction existed — they must show the mistake probably changed the outcome, which raises the bar for defendants trying to win new trials on appeal.
What changes now
The case returns to the Second Circuit, which must now apply the Supreme Court's correct four-part plain-error test to decide whether the missing jury instruction actually affected the outcome of Marcus's trial and whether it seriously harmed the fairness or reputation of the proceedings. This is a final merits ruling on the legal standard, but the ultimate outcome for Marcus's convictions remains undecided pending the remand.
What this does not decide
The Court did not decide whether Marcus's conviction should ultimately stand or be reversed, and it did not decide whether the missing instruction amounted to a constitutional Ex Post Facto Clause violation — it only rejected the appeals court's legal standard and sent the case back for the correct analysis.
Concurrences and dissents
Dissent — Justice Stevens
“The trial error at issue in this case undermined the defendant’s substantial rights by allowing the jury to convict him on the basis of an incorrect belief that lawful conduct was unlawful, and it does not take an elaborate formula to see that.”Stevens's core objection that the error clearly affected the verdict without needing a complex test.
Justice Stevens agreed the Second Circuit used an unusual standard but would have affirmed its judgment anyway, arguing the missing instruction let the jury wrongly believe Marcus's earlier lawful conduct was criminal, distorting its view of the case and likely affecting both verdicts. He also criticized the Court's four-factor plain-error framework itself as overly complex, arguing Rule 52(b)'s plain text asking only whether 'substantial rights' were affected should guide courts, with appellate courts given more discretion rather than a rigid multi-part test.
How the Court got there
The legal reasoning, step by step
- The Court applied its four-part test for 'plain error' review, which lets an appeals court fix a mistake nobody objected to at trial only if there was an error, the error was clear, the error actually affected the trial's outcome, and the error seriously damaged the fairness or reputation of the courts.
- Under the third part of that test, an unobjected-to error normally must be shown to be 'prejudicial' — meaning there's a reasonable probability it changed the trial's outcome — unless the error is a rare 'structural error' that undermines the entire framework of the trial, like a total denial of a lawyer or a biased judge.
- The Court found the missing instruction here was not this kind of rare structural error, because judges routinely evaluate the impact of similar jury-instruction mistakes, and this error was no harder to assess for real-world impact than other ordinary instructional mistakes courts already review for actual effect.
- Because the error wasn't automatically 'substantial' just from existing, the Second Circuit's rule — reversing whenever there was any possibility, however remote, that the jury convicted solely on conduct that predated the law — did not match the requirement that the error actually likely affected the verdict.
- The Court also found the Second Circuit's approach clashed with the fourth part of the test, since an error that almost certainly didn't change the jury's verdict does not seriously damage the fairness or public reputation of the trial process.
- Concluding that the correct four-part test had not been properly applied, the Court determined the case needed to go back so the actual likely impact of the missing instruction could be assessed under the right standard.