There’s a realistic chance the U.S. Supreme Court throws out Ghislaine Maxwell’s child sex trafficking conviction and twenty-year sentence. I don’t like it any more than you do, and I don’t think she’s more than 50 percent likely to prevail, or even, say 30 percent. But Maxwell has a shot, and her chances are far better than the typical Supreme Court appellant.

Maxwell’s last-ditch appeal to the Supreme Court has nothing to do with her actual sex trafficking of minors. Her primary legal argument bears not on whether she received a fair trial, or her substantive guilt. It’s all about basic, anodyne principles of contract law: DOJ made a deal — a bad one maybe, but a deal — and then went back on its word, Maxwell contends.

Maxwell’s appeal springs from a vital inflection point in the sprawling prosecutorial and political mess around Jeffrey Epstein: the reprehensible, indefensible 2007 non-prosecution agreement between Epstein and DOJ prosecutors in the Southern District of Florida, led by then-U.S. Attorney Alexander Acosta.

After an extensive investigation, the FBI identified at least three dozen underage victims, and a prosecutor in Acosta’s office drafted a 60-count indictment that would have subjected Epstein to a decade to life behind bars upon conviction. But – after weeks of furious lobbying by Epstein’s megabucks legal team, which included Alan Dershowitz and Ken Starr – Acosta declined to bring any federal charges. Instead, he gave Epstein a non-prosecution agreement that required him to plead guilty only to low-level Florida state charges of solicitation of prostitution and procuring minors for prostitution. Epstein ultimately served less than 13 months in a minimum-security Palm Beach County facility, much of it free on a “work-release” program at a shadowy newly-formed business called the “Florida Science Foundation,” located at the same address as one of his attorneys.

If you’re appalled, you should be. And it’s about to get worse.

Not only did Acosta go light on Epstein, but he also gave a free pass to other wrongdoers. The non-prosecution agreement provides that “the United States also agrees that it will not institute any criminal charges against any potential co-conspirators of Epstein.”

This is nuts. As a prosecutor, I never offered or even heard of a deal like this one, which broadly protects not only the defendant but also some undefined set of co-conspirators, regardless of the severity of their conduct. Yet Acosta signed off on this bespoke arrangement, which promised to benefit unknown numbers of Epstein-enabling child sex traffickers.

Fast forward a dozen years to 2019. Acosta becomes Trump’s Labor Secretary, and the controversy around his handling of the Epstein case comes roaring back to life. Acosta resigns, and prosecutors in the Southern District of New York pick up the criminal case. They indict Epstein in 2019 (he dies in prison weeks later), and then charge Maxwell in 2020.

Throughout her prosecution, Maxwell has maintained that she is entitled to the benefit of the 2007 Epstein deal, which provided that his co-conspirators would not be charged. Prosecutors responded in the district court and in the Second Circuit Court of Appeals (which covers New York federal courts) that the Southern District of Florida deal binds only that particular federal district, and not the SDNY.  But Maxwell countered, first, that a deal’s a deal: like it or not, DOJ promised not to prosecute co-conspirators back in 2007, and can’t renege now by having some other U.S. attorney handle the case. And Maxwell argued that, while certain parts of the Epstein deal specify that they apply only to the Southern District of Florida, the co-conspirator provision applies to “the United States” – meaning all of DOJ.

A leading precedent on this issue is United States v. Prisco – a case that, it turns out, I prosecuted at the SDNY. Angelo Prisco was a Bronx-based Genovese Family powerhouse. In 2007, the U.S. Attorney’s Office in New Jersey charged the notorious gangster with various crimes but let him off with a soft plea deal to one count of interstate travel in aid of racketeering – and, importantly, a guarantee that he would not be further prosecuted in that federal district.

But a few years later, the FBI brought me a case that resulted in a murder charge against Prisco. Among other evidence, we caught him on tape soliloquizing: “When somebody’s gotta go, they become a cockroach. What do you do with a cockroach? You kill the cockroach, you step on the cockroach, you go about your business. You don’t go calling people up and say, ‘Eh, I stepped on a cockroach last night,’ you know? Just make it done. Hey, I didn’t make it that way, but that’s the way it is.” The guy had a way with words.

We tried Prisco, the jury convicted him, and the judge sentenced him to life. But Prisco argued on appeal that the prior sweetheart deal with the District of New Jersey guaranteed that he would not be further prosecuted federally, and that we in the SDNY had breached that agreement by charging him. The district court and the Second Circuit both rejected Prisco’s claim; the District of New Jersey’s promise was binding only on that district, and not on the SDNY, by the terms of the deal itself. Now the Justice Department has leaned on the Prisco case throughout its briefing on Maxwell, and the Second Circuit cited it in rejecting Maxwell’s appeal.

In one sense, Maxwell has a better argument than Prisco did because the language she cites refers to “the United States” broadly, whereas Prisco (and Epstein himself) received future protection from prosecution only in the specific district of the original plea deals. On the other hand, Maxwell’s argument is strained because she was not even a party to the Epstein deal. It’s questionable whether an outsider would have a legal basis to enforce the agreement, or whether a deal that protects unnamed co-conspirators is so contrary to the public interest that it’s unenforceable in the first place.

So will the Supreme Court hear Maxwell’s appeal? The Court never has to take any case, of course, and the justices traditionally accept only a small fraction — under 5 percent — of the total petitions seeking review. But Maxwell’s case seems to present what lawyers call a “circuit split” — meaning different federal circuit courts of appeals have resolved the same issue differently. Nothing draws the Supreme Court’s attention quite like a circuit split (after all, one of the Court’s primary functions is to ensure uniformity and clarity in application of federal law).

On the other hand, the Court declined to take a case posing a similar issue the last time it was presented to them, back in 2011 in the Prisco case. But that was a decade and a half ago, and four of the nine current justices have joined the Court since then: Justices Neil Gorsuch, Brett Kavanaugh, Amy Coney Barrett, and Ketanji Brown Jackson.

Maxwell’s case offers uncomfortable (if imperfect) parallels to the Bill Cosby debacle, wherein prosecutors convicted the serial sexual predator but ultimately lost their case on appeal because they had gone back on an earlier promise not to prosecute Cosby, which led him to waive his Fifth Amendment right and give incriminating testimony at a civil deposition. Despite the overwhelming record of Cosby’s guilt, he walked free because prosecutors broke their word.

Odds are against Maxwell, on the whole — though she’s got a substantially better chance at gaining traction in the Supreme Court than the average litigant. Whatever the outcome, her appeal argument has some merit, and should serve as an important reminder. No matter how horrific a defendant’s conduct, and no matter how overwhelming the proof of guilt, a cowardly, bad-faith prosecutor like Acosta can fumble it all away.

Elie’s next book, “When You Come at the King: Inside DOJ’s Pursuit of the President from Nixon to Trump,” publishes on September 16. Pre-order here.