Supreme Court Recognizes a “Miscarriage of Justice” Limit on Appeal Waivers

Criminal Defense Lawyer Zak T. Goldstein, Esquire

On June 18, 2026, the United States Supreme Court held that a defendant’s promise not to appeal his sentence cannot be enforced when enforcing it would produce a miscarriage of justice, meaning an error so egregious that it would bring the judicial system into disrepute. Justice Kagan wrote for eight members of the Court in Hunter v. United States, 608 U.S. ___ (2026). Justice Thomas dissented.

The ruling settles a question that had divided the federal courts of appeals for years, and it clarifies when a knowing and voluntary appeal waiver, a standard feature of most federal plea agreements, must give way.

Background

Federal prosecutors charged Munson Hunter III with ten counts of bank and wire fraud arising from a years-long scheme that cost financial institutions about half a million dollars. Hunter signed a written plea agreement. He pleaded guilty to one count of aiding and abetting wire fraud, and in exchange, the government dismissed the other nine counts and agreed not to prosecute him for the conduct they described.

The agreement included an appeal waiver. Hunter gave up the right to appeal both his conviction and his sentence, reserving only the right to raise a claim of ineffective assistance of counsel. It also stated that any modification of its terms had to be in writing and signed by all parties. The district court accepted the plea as knowing and voluntary.

At sentencing, the Probation Office recommended that Hunter, as a condition of supervised release, “take all mental-health medications that are prescribed by [his] treating physician.” Hunter objected, telling the court he did not want to be “forced to medicate.” The court imposed the condition anyway and sentenced Hunter to 51 months in prison followed by three years of supervised release. As the hearing closed, the judge told Hunter, “You have a right to appeal.” When the court asked whether counsel had anything to add, the defense answered, “Nothing from the defense,” and the prosecutor said, “Your Honor, I believe—well, no. I—no.”

Hunter appealed the medication condition, arguing that it infringed a due process liberty interest in refusing unwanted mental-health medication. The government moved to dismiss based on the appeal waiver. The Fifth Circuit dismissed the appeal. Under its precedent, an appeal waiver gives way in only two situations: when ineffective assistance of counsel tainted the waiver, and when the sentence exceeds the statutory maximum. Neither applied.

The Court’s Decision

The Supreme Court first rejected Hunter’s argument that the sentencing hearing itself had undone his waiver. The judge’s misstatement about a right to appeal did not modify the plea agreement, which required any change to be in writing and signed by both sides, and nothing at the hearing reflected the mutual agreement a modification requires. The government’s silence did not surrender its right to enforce the waiver either. The proper time to assert that right, the Court explained, comes after a defendant files a notice of appeal, not at sentencing. The Court noted that it had reached a parallel result in Class v. United States, 583 U.S. 174 (2018).

The Court then reached the central question: whether the government’s right to enforce an appeal waiver has limits. It held that it does. Courts are not bystanders to these waivers. A district court must accept a plea agreement before an appeal waiver takes effect, and a court of appeals decides whether the waiver will be enforced at all. Because enforcement can lock an unlawful sentence into place, the Court reasoned, the standard for enforcing waivers implicates the integrity of the judiciary, not only the interests of the parties. Relying on Wheat v. United States, 486 U.S. 153 (1988), and United States v. Mezzanatto, 513 U.S. 196 (1995), the Court concluded that enforcing every waiver automatically would risk institutional harm.

The Court adopted the standard that most federal circuits already apply: an appeal waiver is unenforceable when enforcing it would result in a miscarriage of justice. It emphasized that this sets a high bar. The error must be obvious, not one a judge could reasonably make, and of a kind that would undermine public confidence in the courts. Ordinary mistakes in applying sentencing law do not qualify.

The Court offered three illustrations of errors that could clear that bar. A sentence exceeding the statutory maximum qualifies. So does a sentence infected with a blatant constitutional error, such as reliance on an impermissible factor like race or an unconstitutional condition of supervised release. And so does a sentence imposed without some minimum of civilized procedure. The Court described these as examples rather than an exhaustive list.

The Court did not decide whether the medication condition in Hunter’s case met the standard. Describing itself as “a court of review, not of first view,” it vacated the Fifth Circuit’s judgment and sent the case back for that court to apply the new standard.

The Concurrences and the Dissent

Justice Gorsuch, joined by Justices Sotomayor and Jackson, concurred. He traced the rise of plea bargaining and appeal waivers and raised, for a future case, whether a defendant can knowingly waive the right to appeal a sentence he cannot yet foresee. Justice Kavanaugh, joined by Justices Alito and Barrett, wrote separately to stress that the exception reaches only extreme cases, and to register his disagreement with what he read as a broader approach in Justice Gorsuch’s opinion. Justice Barrett added that the decision rests on established waiver principles rather than any supervisory power over the lower courts.

Justice Thomas dissented. He argued that the Court identified no source of law for its new exception. The right to appeal a sentence is a statutory right of relatively modern origin, he wrote, and a defendant who waives it in a valid plea agreement should be held to that bargain.

The Takeaway

Hunter confirms that a signed appeal waiver is not absolute, though the Court designed the exception to be narrow. For defendants in Pennsylvania and elsewhere in the Third Circuit, the decision largely ratifies existing practice, because the Third Circuit has applied a miscarriage-of-justice limit since United States v. Khattak, 273 F.3d 557 (3d Cir. 2001). The remaining questions return to the courts of appeals, which will decide, case by case, which sentencing errors are serious enough to overcome a waiver.

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