The Supreme Court ruled 8-1 last week that appeal waivers in federal plea agreements are not ironclad, and that courts may refuse to enforce them when doing so would produce a "miscarriage of justice." The decision in Hunter v. United States adopts a flexible exception that most federal circuits already recognized, but that now carries the weight of the nation's highest court. Justice Clarence Thomas, the lone dissenter, warned the ruling could erode the certainty prosecutors depend on when striking plea bargains.
The case involved Munson P. Hunter III, a Texas man originally charged with 10 counts of bank and wire fraud tied to roughly $500,000 in losses. Hunter struck a deal: he pleaded guilty to a single count of aiding and abetting wire fraud, the government dropped the other nine counts, and both sides agreed not to pursue additional charges based on the same conduct. In exchange, Hunter waived his right to appeal his conviction or sentence, with one narrow exception for claims of ineffective assistance of counsel.
The district court accepted the plea as knowing and voluntary, then sentenced Hunter to 51 months in prison, three years of supervised release, and restitution. But the sentencing hearing introduced a wrinkle that would travel all the way to the Supreme Court.
At sentencing, the U.S. 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 requirement on the spot.
Then the judge told Hunter he had "a right to appeal."
Hunter took the judge at his word and appealed the medication condition to the Fifth Circuit Court of Appeals. The Fifth Circuit dismissed the appeal, holding that the written waiver in his plea agreement barred it. Hunter then petitioned the Supreme Court.
The majority, in an opinion authored by Justice Elena Kagan and joined by Chief Justice John Roberts along with Justices Samuel Alito, Sonia Sotomayor, Neil Gorsuch, Brett Kavanaugh, Amy Coney Barrett, and Ketanji Brown Jackson, sided with Hunter on the broader legal question, though not exactly on the grounds he raised.
The court first rejected Hunter's argument that the district judge's courtroom statement about his right to appeal effectively rewrote the plea agreement. The majority explained that plea agreements function as contracts. A judge's mistaken remark at sentencing cannot unilaterally modify clear written terms, and the plea agreement specifically required any modifications to be in writing and signed by all parties.
But the court did not stop there. It adopted a "miscarriage of justice" exception to appeal waivers, one that most federal circuits had already applied in some form. Under this standard, a waiver may be unenforceable when enforcing it would preserve an "egregious error" that brings the judicial system into disrepute.
Kagan's opinion emphasized that courts play a central role in approving plea agreements and deciding whether to enforce them. The majority stressed that the exception is narrow: ordinary sentencing disputes and routine disagreements over guideline calculations will not qualify. Only extraordinary legal errors rise to the level of a miscarriage of justice.
The court then remanded Hunter's case to the Fifth Circuit to determine whether the mandatory-medication supervised-release condition meets that standard.
The 8-1 vote masked real disagreements about what the ruling means going forward. Justice Kavanaugh authored a separate concurrence, joined by Justices Alito and Barrett, emphasizing the limited scope of the court's holding. Barrett also wrote separately to reinforce the same point. Their message was clear: don't read this as a green light for defendants to relitigate every plea deal.
The court has shown a willingness to produce unexpected coalitions in recent terms, and this case was no different. Justice Gorsuch authored his own concurrence, joined by Justices Sotomayor and Jackson, a pairing that would raise eyebrows in most other contexts. Their concurrence raised broader concerns about the modern plea-bargaining system itself.
That concern is not trivial. The court noted that approximately 90 percent of federal convictions result from guilty pleas. The vast majority of those convictions flow from plea agreements. When nearly the entire federal criminal docket runs through negotiated deals rather than jury trials, the terms of those deals, including appeal waivers, carry enormous weight.
Justice Thomas dissented, alone, as he has done before on questions where he believes the court is loosening structural safeguards. Thomas has not been shy about rebuking his colleagues when he believes they are departing from constitutional principle.
In Hunter, Thomas argued that the petitioner knowingly and voluntarily waived his appellate rights and should be held to that agreement. He warned that the ruling may weaken the certainty prosecutors rely upon in plea negotiations. Introducing a flexible "miscarriage of justice" exception, Thomas argued, threatens the finality that makes plea bargaining workable in the first place.
He cautioned that defendants will now have a new basis to challenge appeal waivers, a prediction that prosecutors across the country are likely taking seriously.
Thomas's willingness to stand as the sole dissenter is consistent with his broader judicial posture. He has repeatedly staked out aggressive positions in cases where he believes the court is trading legal clarity for equitable flexibility.
The immediate practical effect is limited. Hunter's case goes back to the Fifth Circuit, which must now decide whether a court-ordered requirement to take all prescribed mental-health medications qualifies as the kind of egregious error that undermines public confidence in the justice system. That is a high bar, and the Supreme Court went out of its way to say so.
But the broader signal matters. Federal prosecutors negotiate plea agreements with the understanding that appeal waivers will stick. Those waivers are a key part of the bargain, defendants get reduced charges or sentencing concessions, and the government gets finality. If waivers become more porous, the cost of plea deals shifts.
The pattern of 8-1 rulings with Thomas in lone dissent has become a recurring feature of this court. In United States v. Rahimi, the court voted 8-1 to uphold a federal law banning firearm possession for individuals under domestic violence restraining orders, with Thomas again as the sole holdout. There, Thomas argued the law lacked historical justification and stripped individuals of gun rights without due process, as AP News reported. That ruling prompted the Justice Department to immediately leverage the decision in other cases, including filing a brief the same day to bolster its prosecution of Hunter Biden's federal gun conviction, as National Review detailed.
The Hunter v. United States ruling does not carry the same political charge as a gun case. But it touches the machinery of federal criminal justice at its most fundamental level. With nine out of ten federal convictions coming through plea agreements, any shift in the enforceability of those deals ripples across thousands of cases.
The court has also shown in other recent terms that lopsided votes do not always mean simple cases. The concurrences in Hunter reveal justices who agree on the result but disagree sharply on the reasoning and the scope. Kavanaugh, Alito, and Barrett want the exception kept on a short leash. Gorsuch, Sotomayor, and Jackson want to ask harder questions about the plea-bargaining system itself.
Those fault lines will matter the next time a defendant invokes the miscarriage-of-justice exception, and someone will, soon.
Thomas's dissent raises the right concern, even if seven of his colleagues disagreed. Plea agreements work because both sides can count on them. Defendants waive rights in exchange for leniency. Prosecutors dismiss charges in exchange for certainty. When the court introduces a judge-made safety valve, however narrow, it invites litigation over where the valve opens.
The majority insists the exception is limited to egregious errors. But "egregious" is a word that expands in the hands of creative defense attorneys. The court did not define it with precision, and the Fifth Circuit now gets the first crack at drawing the line.
For the roughly 90 percent of federal defendants who plead guilty, the ruling changes the landscape in a small but real way. For prosecutors, it adds a variable to every negotiation. And for the justice system as a whole, it trades a measure of finality for a measure of fairness, a trade that sounds reasonable in the abstract but gets messy in practice.
When nearly every federal conviction runs through a negotiated deal instead of a jury trial, the government had better make sure those deals are airtight. If they aren't, the court just told us, don't expect the waiver to do the cleanup.
