Supreme Court creates ‘miscarriage of Justice’ exception to plea-deal appeal waivers

In a decision that received far less attention than some of the Supreme Court’s headline-grabbing cases this term, the court issued a ruling late last week in Hunter v. United States that could have significant consequences for federal criminal cases.

By an 8–1 vote, the court held that appeal waivers in plea agreements are not absolute. A waiver may be unenforceable when enforcing it would result in a “miscarriage of justice” – that is, when it would leave in place an egregious error that undermines confidence in the judicial system.

While not the kind of blockbuster ruling that dominates headlines like those involving abortion, guns or executive power, the decision carries significant implications for the criminal justice system. 

Because the vast majority of federal convictions result from plea agreements, appeal waivers have become a routine tool for prosecutors seeking finality. The court’s decision creates a new avenue for defendants to challenge their sentences despite those waivers, prompting concerns from critics that the ruling could encourage additional post-conviction litigation.

The Facts of the Case

The dispute arose from the prosecution of Munson P. Hunter III, a Texas man charged with 10 counts of bank and wire fraud involving roughly $500,000 in losses. Rather than risk conviction on all counts – which carried the possibility of an extremely lengthy sentence – Hunter entered into a plea agreement. He pleaded guilty to one count of aiding and abetting wire fraud, while the government dismissed the remaining charges and agreed not to pursue additional charges based on the same conduct.

As part of the agreement, Hunter knowingly waived his right to appeal his conviction or sentence, except for claims of ineffective assistance of counsel. The agreement emphasized that any modifications had to be in writing and signed by all parties. The district court accepted the plea as knowing and voluntary.

At sentencing, matters took a turn that became central to the dispute. The Probation Office recommended, and the judge imposed, a condition of supervised release requiring Hunter to participate in a mental-health treatment program and take all mental-health medications prescribed by his treating physician. Hunter objected to the mandatory-medication component, arguing it infringed on his fundamental due process liberty interest in refusing unwanted medication. 

The judge imposed a sentence of 51 months in prison, followed by three years of supervised release, plus restitution. Near the end of the hearing, the judge told Hunter he had “a right to appeal,” and neither side pushed back on that statement.

Hunter appealed the medication requirement, but the Fifth Circuit dismissed the appeal based on the waiver. Under the court’s precedent, appeal waivers are generally enforceable except in two limited circumstances: ineffective assistance of counsel or a sentence exceeding the statutory maximum. Hunter’s claim fit neither exception.

The Supreme Court’s Decision

Justice Elena Kagan authored the majority opinion, joined by Chief Justice John Roberts and Justices Samuel Alito, Sonia Sotomayor, Neil Gorsuch, Brett Kavanaugh, Amy Coney Barrett and Ketanji Brown Jackson.

The court first rejected Hunter’s argument that the district judge’s statement about appeal rights altered the plea agreement. Because plea agreements function as contracts, the court explained, a judge’s mistaken statement at sentencing cannot unilaterally modify clear written terms.

The court then addressed the broader question of whether appeal waivers must always be enforced. 

Kagan emphasized that courts play a central role in approving plea agreements and deciding whether to enforce them. According to the majority, rigid enforcement of appeal waivers, even in cases involving extraordinary legal errors, could damage public confidence in the justice system.

The court therefore adopted a “miscarriage of justice” exception already recognized by most federal circuits. Under that standard, an appeal waiver cannot be enforced when doing so would preserve an “egregious error” that brings the judicial system into disrepute.

In addition, the court stressed that the exception is narrow. Ordinary sentencing disputes or routine guideline disagreements will not qualify. Instead, the standard is aimed at extraordinary circumstances, such as sentences exceeding statutory limits, blatant constitutional violations or other fundamentally unlawful sentencing conditions.

The justices sent Hunter’s case back to the Fifth Circuit to determine whether the mandatory-medication requirement meets that demanding standard.

Several justices also wrote separately. 

Justice Gorsuch, joined by Justices Sotomayor and Jackson, raised broader concerns about the modern plea-bargaining system. Justice Kavanaugh, joined by Justices Alito and Barrett, and Justice Barrett herself wrote separately to emphasize the limited scope of the court’s holding.

Justice Thomas’s Lone Dissent

Justice Clarence Thomas was the sole dissenter.

Thomas argued that Hunter knowingly and voluntarily agreed to waive his appellate rights and should therefore be bound by that agreement. In his view, the majority created an exception untethered from the law and driven instead by policy concerns about fairness and institutional legitimacy.

He warned that the ruling may weaken the certainty prosecutors rely upon when negotiating plea agreements. Hunter, Thomas noted, received a substantial benefit by avoiding prosecution on nine additional counts carrying potentially severe penalties.

More broadly, Thomas argued that introducing a flexible “miscarriage of justice” exception threatens the finality that plea bargains are designed to provide. Even if the standard is intended to be narrow, he cautioned that defendants will now have a new basis to challenge appeal waivers, potentially increasing litigation and creating uncertainty in future plea negotiations.

Why the Decision Matters

The ruling does not eliminate appeal waivers, nor does it dramatically expand defendants’ rights. Most appeal waivers will remain enforceable, and the court emphasized that the exception applies only in rare and exceptional circumstances.

Still, the decision could have important practical effects. In a criminal justice system in which 90% of federal convictions result from guilty pleas, even a limited exception may encourage additional challenges to supervised-release conditions, restitution orders, and other sentencing provisions that raise constitutional concerns.

Supporters of the decision argue that it provides an essential safeguard against extreme judicial errors and helps preserve public confidence in the courts. Critics counter that it risks undermining the finality of plea agreements and could lead to more appeals from incarcerated defendants.

As lower courts begin applying the new standard, the scope of the court’s ruling will become clearer. For now, Hunter stands for a straightforward principle: appeal waivers remain powerful tools, but they cannot be used to shield the most serious and extraordinary errors from judicial review.