Convicted at trial?
There may be hope now.

The precise holding. An appeal waiver in a plea agreement is unenforceable when enforcing it would result in a miscarriage of justice — when it would leave in place "the kind of egregious error that would bring the judicial system into disrepute." The Court adopted the majority rule of the circuits and vacated the Fifth Circuit, which had allowed only two escape hatches (IAC-tainted waiver; sentence above the statutory max).

Why the Court got there. Courts are "too enmeshed" in appeal waivers to escape responsibility for their results: a district judge must accept the waiver (Fed. R. Crim. P. 11(c)(3)(A), Santobello), and only a court of appeals gives it real-world effect. Automatic enforcement "risks institutional harm" — Wheat, 486 U.S. 153; Mezzanatto, 513 U.S. 196 (the "twelve orangutans" principle: some minimums of civilized procedure cannot be signed away).

The three named categories (examples, not an exclusive list): (1) a sentence exceeding the statutory maximum; (2) a sentence infected with blatant constitutional error — race or religion weighed at sentencing, or a constitutionally infirm supervised-release condition (Hunter's own claim: forced mental-health medication); (3) a sentence imposed without "some minimum of civilized procedure."

The bar is high — respect it. The error must be obvious ("not one a judge could reasonably make") and of the type that undermines public confidence. Standard Guidelines miscalculations and ordinary sentencing mistakes do not void a waiver. Pleading Hunter for garden-variety error gets dismissed fast — and burns credibility.

The full Hunter toolkit. A waiver must still be knowing and voluntary (Brady v. United States), and one tainted by ineffective assistance is unenforceable (Hill v. Lockhart). A judge's stray "you have a right to appeal" at sentencing does not modify the deal (Class v. United States, 583 U.S. 174) — don't hang your case on it. And never forget 18 U.S.C. § 3583(e)(2): supervised-release conditions can be challenged by motion to modify at any time, no appeal needed.

How this house uses it. On direct appeal: name the category, prove the error is obvious, and invoke the miscarriage-of-justice exception expressly. In post-conviction work: pair Hunter's principle — finality never outranks integrity — with the actual-innocence gateway (Schlup, House, McQuiggin) and the merits predicates (Brady, Napue, Strickland). That is precisely what the builder below drafts.