United States v. Marcus
The Supreme Court rejected a Second Circuit rule that automatically threw out a conviction whenever there was any chance, however remote, that a jury convicted someone based only on conduct that happened before the relevant law took effect.
The Court held that this kind of unraised error must still be shown to have actually affected the trial's outcome and to seriously undermine the fairness of the proceedings before an appeals court can step in, sending the case back for the Second Circuit to apply that stricter standard.
“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 was rejecting.
How it got here: A jury convicted Marcus at trial; the Second Circuit vacated the conviction on appeal under a broad plain-error rule; the government asked the Supreme Court to review that standard.
The Case in Depth
What happened
Glenn Marcus was charged with forced labor and sex trafficking covering conduct from January 1999 to October 2001. The statutes he was convicted under only became law in October 2000. At trial no one told the jury it could not convict based solely on conduct from before the law existed, and Marcus never objected to this omission before appealing.
The question before the Court
When a defendant never objected at trial that some of his crimes happened before the law existed, must an appeals court automatically order a new trial just because there's some chance the jury convicted him only on that earlier conduct?
Why it matters
Defendants who fail to object to trial errors at the time now face a real, not merely theoretical, burden on appeal: showing the error actually likely changed the verdict. Appeals courts nationwide, especially the Second Circuit, must abandon looser 'any possibility' standards, making it harder to win reversals on errors first raised on appeal.
What changes now
The case returns to the Second Circuit, which must now apply the Supreme Court's stricter plain-error framework to decide whether the trial error actually affected the outcome of Marcus's trial and seriously harmed the fairness or integrity of the proceedings. This is a final merits ruling on the legal standard, but the ultimate outcome for Marcus's conviction remains undecided pending that further review.
What this does not decide
The Court did not decide whether Marcus's own conviction should actually be reversed — it only rejected the legal standard the Second Circuit used and sent the case back for that court to reapply the correct plain-error test to Marcus's specific trial record.
Concurrences and dissents
Dissent — Justice Stevens
“it does not take an elaborate formula to see that”Stevens arguing the trial error obviously prejudiced Marcus without a complex legal test.
Justice Stevens agreed the Second Circuit used a novel standard but would still have affirmed its judgment, finding the trial error genuinely prejudiced Marcus by letting the jury believe lawful pre-enactment conduct was criminal, tainting both verdicts. He separately criticized the Court's four-factor plain-error framework itself as overly complex, arguing Rule 52(b)'s plain text sets a simple 'substantial rights' standard that appellate courts should apply with discretion rather than through an elaborate 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 is an error that is clear, that actually affected the outcome, and that seriously harms the fairness or reputation of the courts.
- Under the third part of that test, an unobjected-to error normally must be shown to have created a reasonable probability that it changed the trial's result — mere theoretical possibility is not enough.
- The Court asked whether this type of error belonged to a very narrow category called 'structural errors' — mistakes so fundamental (like being denied a lawyer entirely) that courts don't require proof they changed the outcome. It found this error did not qualify, because a simple jury instruction could have prevented it, just like other ordinary instructional mistakes courts already treat as fixable through a probability analysis.
- The Court also rejected the argument that mislabeling the mistake an 'Ex Post Facto Clause' violation should make it an automatic structural error, noting the true constitutional hook was the Due Process Clause and that errors of this kind vary too much in seriousness to always be treated the same way.
- Turning to the fourth part of the test, the Court reasoned that when the risk a jury actually relied on the improper evidence is tiny — for example, a few days of pre-law conduct against years of otherwise valid conduct — letting the conviction stand would not seriously damage the fairness or public reputation of the courts.
- Because the Second Circuit's rule found error automatically from any conceivable possibility rather than requiring proof of real harm, it conflicted with both the third and fourth parts of the Court's plain-error framework.
Doctrinal impact
Cases affected by this decision
Reaffirms Olano (507 U. S. 725)
Court relies on Olano's requirement that plain errors normally must be shown to be prejudicial, not merely possible.
Reaffirms Puckett (556 U. S. 129)
Court reaffirms Puckett's four-part plain-error framework as the governing standard.