by David Kim

The Supreme Court of the United States held that a criminal defendant’s agreement not to appeal a sentence is unenforceable when enforcement would produce a miscarriage of justice. Defining the threshold, the Court stated that a waiver may be set aside only where the sentence contains “the kind of egregious error that would bring the judicial system into disrepute.” In resolving a longstanding circuit split, the Court adopted the approach embraced by the majority of Courts of Appeals, rejecting both the Government’s contention that knowing and voluntary appeal waivers are always enforceable and the Fifth Circuit’s framework recognizing only two narrow exceptions. The Court separately held that the sentencing court’s erroneous advisement of appeal rights and the prosecutor’s silence did not modify the waiver.

Background

Munson Hunter III was charged with 10 counts of bank and wire fraud for a scheme costing financial institutions approximately half a million dollars. He entered a plea agreement under which he pleaded guilty to one count of aiding and abetting wire fraud, and the Government dismissed the remaining charges. The agreement included a provision through which Hunter “knowingly and voluntarily waive[d] the right to appeal” his conviction and sentence, preserving only the right to raise ineffective-assistance-of-counsel claims and specified that “[a]ny modification” of its terms “must be in writing and signed by all parties.”

The U.S. District Court for the Southern District of Texas imposed 51 months’ imprisonment followed by three years of supervised release, including a contested condition requiring Hunter to take all prescribed mental-health medications. Hunter had objected to the mandatory-medication component. At the hearing’s close, the court erroneously told Hunter he had “a right to appeal.” The prosecutor started to respond but ultimately said nothing.

Hunter timely appealed, arguing the medication condition violated his fundamental due process liberty interest in refusing unwanted psychiatric medication. The Fifth Circuit dismissed, holding that circuit precedent recognized only two exceptions to appeal-waiver enforcement: (1) when the waiver itself was tainted by ineffective assistance of counsel and (2) when the sentence exceeded the statutory maximum. United States v. Barnes, 953 F.3d 383 (5th Cir. 2020). The Supreme Court granted certiorari to resolve a split among the circuits.

Analysis

The Court first addressed Hunter’s contention that the trial court’s erroneous advisement, together with the prosecutor’s silence, voided the appeal waiver. The plea agreement’s express requirement that modifications be in writing and signed by all parties foreclosed any oral alteration, according to the Court. Even setting that provision aside, the Court found no mutual assent between the parties. “There was neither an offer nor an acceptance by those parties,” the Court observed, “and so no conceivable meeting of the minds.” Because the parties’ intent governs their agreement, the trial court’s representation could not alter its terms.

Similarly, the Court rejected Hunter’s forfeiture argument. While forfeiture typically results from silence, United States v. Olano, 507 U.S. 725 (1993), the relevant question is timeliness. The Government’s proper moment to invoke the waiver comes after a defendant files a notice of appeal. Because the prosecutor’s silence occurred at sentencing, it was not “the failure to make the timely assertion” of the enforcement right, the Court stated. Id. The Court found this result consistent with Class v. United States, 583 U.S. 174 (2018), where a defendant’s acquiescence to a court’s mistaken advisement regarding appeal rights did not waive his own right to appeal. By the same reasoning, the Government’s silence here did not surrender its right to enforce the waiver, the Court concluded.

The Miscarriage-of-Justice Standard and the Circuit Split

The circuits had divided sharply on when an otherwise valid appeal waiver becomes unenforceable beyond its own stated terms. A majority of circuits, including the First, Second, Third, Fourth, Eighth, Ninth, Tenth, and D.C. Circuits, had adopted a miscarriage-of-justice standard. See United States v. Boudreau, 58 F.4th 26 (1st Cir. 2023); United States v. Riggi, 649 F.3d 143 (2d Cir. 2011); United States v. Khattak, 273 F.3d 557 (3d Cir. 2001); United States v. Smith, 134 F.4th 248 (4th Cir. 2025); United States v. Andis, 333 F.3d 886 (8th Cir. 2003); United States v. Wells, 29 F.4th 580 (9th Cir. 2022); United States v. Holzer, 32 F.4th 875 (10th Cir. 2022); United States v. Guillen, 561 F.3d 527 (D.C. Cir. 2009). A minority, comprising the Fifth, Sixth, Seventh, and Eleventh Circuits, recognized only a few discrete circumstances permitting appeal despite a waiver. See Barnes; Portis v. United States, 33 F.4th 331 (6th Cir. 2022); United States v. Nulf, 978 F.3d 504 (7th Cir. 2020); King v. United States, 41 F.4th 1363 (11th Cir. 2022). The Government’s position was even stricter, maintaining that knowing and voluntary waivers are enforceable without exception.

The Court focused its analysis on the judiciary’s institutional involvement at every stage of a waiver’s operation. District Courts must exercise “sound judicial discretion” in accepting a plea agreement before any appeal waiver can take effect, the Court observed. Santobello v. New York, 404 U.S. 257 (1971). Courts of Appeals then hold exclusive control over enforcement, and their decision to enforce will “cement into place” the sentence “whether or not lawful.” Because courts are “in the middle of, and partly responsible for, appeal waivers and their results,” automatic enforcement could “risk[] institutional harm,” the Court reasoned. In Wheat v. United States, 486 U.S. 153 (1988), the Supreme Court had recognized the federal courts’ independent “institutional interest” in proceedings that “appear fair to all who observe them.” And in United States v. Mezzanatto, 513 U.S. 196 (1995), the Supreme Court acknowledged that some rules are “so fundamental” their waiver could “irreparably discredit[] the federal courts.”

The Court explained that the Government’s absolutist rule could not withstand the Fifth Circuit’s own concession that waivers are unenforceable when a sentence exceeds the statutory maximum. Other scenarios equally at odds with judicial legitimacy fell outside both the Government’s and the Fifth Circuit’s frameworks, e.g., a judge who unconstitutionally weighed race or religion in sentencing, a supervised-release condition prohibiting pregnancy, or a sentence chosen by “an orangutan.” “However certain the parties’ agreement,” the Court stated, “the courts are too enmeshed in its approval and implementation to escape responsibility for such results.”

Under the standard the Court adopted, the sentencing error must be “obvious – not one a judge could reasonably make” and “of the type that would undermine public confidence in the judiciary.” Routine sentencing mistakes do not satisfy that standard. Allowing such errors to override waivers could diminish the utility of waivers and “induce fewer concessions to a defendant,” the Court warned. The standard instead functions as “a safety valve for extreme cases – a way out of a waiver when the justice system’s basic integrity is at stake.”

The Court provided three illustrative categories of qualifying errors, expressly declining to be exhaustive: (1) a sentence exceeding statutory authorization, (2) a sentence infected with a blatant constitutional violation, such as reliance on a constitutionally impermissible factor or imposition of a constitutionally infirm supervised-release condition, and (3) a sentence imposed without “some minimum of civilized procedure.” The Court doubted that this limited exception would “open the floodgates,” observing that circuits already applying the standard had not been inundated with appeals.

Conclusion

The Court declined to determine whether Hunter’s challenge to the mandatory-medication condition satisfies the newly announced standard, describing itself as “a court of review, not of first view.” Cutter v. Wilkinson, 544 U.S. 709 (2005).

Accordingly, the Court vacated the Fifth Circuit’s judgment and remanded for proceedings consistent with its opinion. See: Hunter v. United States, 2026 U.S. LEXIS 2558 (2026).  

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