Aug. 12, 2025 – A mistrial based on a misunderstanding of Wisconsin’s State v. Denny led to unconstitutional double jeopardy, the U.S. Court of Appeals for the Seventh Circuit held recently in Mitchell D. Green v. Milwaukee County Circuit Court, No. 24-2980 (Aug. 1, 2025).

The reversal of the U.S. District Court for the Eastern District of Wisconsin resulted in Green receiving the requested writ of habeas corpus, freeing him from retrial.

“By relying on a mistake about what the law requires, the trial court failed to exercise sound discretion,” wrote Judge Frank H. Easterbrook for the unanimous panel that included Judges Joshua P. Kolar and Nancy L. Maldonado.

‘Denny Witness’

Green faced trial in Milwaukee County Circuit Court on a charge of trafficking a child and related offenses, based principally on the victim’s testimony that Green “had driven her to a hotel, where he forced her to engage in a sex act.”

Green’s first witness in his defense was his cousin, Jonathan Cousin, who said he “had driven the minor to the hotel,” although he didn’t know the purpose.

Green listed Cousin on his witness list five months before trial, and the prosecution didn’t object to Cousin’s testimony. The prosecution began cross-examination.

After lunch, however, the prosecutor argued that Cousin was “Denny witness” – a witness “who testifies that they rather than the defendant committed the crime” – requiring pretrial notice under State v. Denny, 120 Wis. 2d 614 (Ct. App. 1984).

The circuit court judge agreed with the prosecution. The need for notice and hearing on admissibility, the judge decided, could not be cured by jury instructions.

Green objected to the mistrial and filed a motion to dismiss. The circuit court denied the motion. On interlocutory appeal, the Wisconsin Court of Appeals, No. 2021AP267-CR (Mar. 22, 2022), held the mistrial erroneous, but the Wisconsin Supreme Court, 2023 WI 57, reversed.

‘Manifest Necessity’

A writ of habeas corpus – a test of whether detention is legal – under 28 U.S.C. section 2241(c)(3) results if the defendant is “in custody in violation of the Constitution.”

Green qualifies because he’s on a $1,500 bond, a sufficient loss of liberty to fall within the statute’s protection, Judge Easterbrook explained.

“Retrial following a mistrial declared over a defendant’s objection is proper only if the mistrial was supported by ‘manifest necessity,’” Judge Easterbrook said.

Absence of “manifest necessity” means the defendant’s retrial would violate the constitutional protection against double jeopardy – a second trial for the same crime.

To avoid that constitutional infirmity, a trial judge considering mistrial “must exercise ‘sound discretion’ and consider” the defendant’s interest in facing a verdict from the currently empaneled jury, “which might already be favorable to him.”

Pretrial Notice?

Green’s trial judge justified mistrial “on the assumption that Denny requires pretrial notice,” but “Denny establishes an admissibility standard [under Wisconsin law], not a notice requirement,” Judge Easterbrook explained.

“We cannot find a pretrial-notice requirement that was in effect before Green’s trial (or today, for that matter),” Judge Easterbrook began in documenting its absence.

“Apparently neither could the Attorney General of Wisconsin, the trial judge, the Court of Appeals of Wisconsin, the Supreme Court of Wisconsin, or the [federal] district court.

“Such a requirement might come from a statute, rule, or judicial decision, but no one has pointed to any of these sources, and our search did not reveal one.”

The Wisconsin Supreme Court’s decision affirming the mistrial did not endorse pretrial Denny disclosures, Judge Easterbrook explained.

The trial arose from “a procedural quirk,” Judge Easterbrook wrote. In Milwaukee County, it’s common for a case to be “‘spun’ or assigned to a new judge” based on that day’s scheduling requirements.

The new judge assumed that the previously assigned judge had ruled on the prosecution’s motion in limine, requesting to exclude Cousins’ testimony, from five months earlier – although no judge had.

The Wisconsin Supreme Court found that was enough, but it wasn’t for the federal court. “[W]e do not understand how ‘manifest necessity’ can be established by presuming something contrary to fact,” Judge Easterbrook said.

Notice of the “Denny witness” existed from that motion in limine, Judge Easterbrook said, among other common ways the issue appears before trial – such as a reminder to the judge or a discovery demand – but none of those other possibilities happened.

“Defense counsel need not comply with rulings never made,” Judge Easterbrook noted.

Alternatives

“So where was the ‘manifest necessity’ to end the trial?” Judge Easterbrook asked. “The jury did not hear inadmissible testimony,” the trial judge ruled the testimony admissible under Denny for retrial, and Green had Cousin on his witness list five months before trial.

“Even if there was an error that necessitated correction,” Judge Easterbrook said, other reasonable alternatives short of mistrial remained available.

A curative jury instruction, rejected by the trial judge, could have done the job.

Another alternative often used, Judge Easterbrook said, would have involved dismissing the jury for a hearing on the testimony “and if necessary giving the prosecutor more time to assemble rebuttal evidence.”

“Even now, the prosecution does not argue that a lack of pretrial notice affected its cross-examination of Cousin,” Judge Easterbrook explained. “A second trial therefore would be identical to the first.”

As a result, the Court of Appeals reversed the district court and remanded the case for the federal district court “to issue an unconditional writ.”

This article was originally published on the State Bar of Wisconsin’s Wisbar Court Review blog, which covers case decisions and other developments in the Wisconsin Supreme Court, the Wisconsin Court of Appeals, and the U.S. Court of Appeals for the Seventh Circuit. To contribute to this blog, contact Joe Forward.