State v. Stroup
Montana Supreme Court (describing orders of the Fourth Judicial District Court, Missoula County) · Mont. · Montana bar guidance
Conduct
Here, as the defendant alleged, a defense motion to dismiss was filed with appended research materials and without the AI-use disclosure the district's Rule 3(G) requires.
Consequence
On the defendant's account, defense filings were rejected with leave to cure and trial was vacated; the Montana Supreme Court called the rejections sanctions Rule 3(G) permits.
Lesson
Here, on the defendant's account, a missing AI-disclosure certification was followed by rejected filings, which the Montana Supreme Court treated as sanctions the local rule permits.
Verified October 1, 2026
- Citation
- State v. Stroup, No. PR 26-0001, Amended Order (Mont. June 9, 2026) (Swanson, C.J.) (describing the March 13, 2026 Order of Rejection in State v. Stroup, No. DC-24-575, Mont. 4th Jud. Dist. Ct., Missoula County, Larson, J.)
- Decided
- June 9, 2026
Summary
In a Missoula County criminal case (No. DC-24-575), defense counsel filed a motion to dismiss on February 9, 2026. As the Montana Supreme Court recounted the defendant's allegations, the filing inadvertently included "appended research and work-product materials," and ten days later counsel filed a "corrected" motion "with full Local Rule 3(g) certification." The Supreme Court read this as implying that the original filing was prepared with generative AI but lacked the disclosure that the Fourth Judicial District's Rule 3(G) requires. According to the same allegations, District Judge John W. Larson vacated the trial date and on March 13, 2026 entered an Order of Rejection rejecting all defense filings, with leave to cure, taking judicial notice that defense counsel had allegedly filed documents in two other cases before him that also failed to disclose AI use. That order said the rejections "underline not only the inept use of GenAI but also an unacceptable level of practice before this Court."
- AI tool:
- Unidentified (the order describes the filing as one Stroup implies was prepared with generative AI without the required disclosure; no tool is named)
What sanction did the court impose?
The defendant moved to disqualify Judge Larson for bias. Chief Justice Cory J. Swanson's amended order of June 9, 2026 considered the motion on its merits and held that "[t]he fact that Judge Larson chose to impose sanctions of a kind permitted under Local Rule 3(G) is insufficient to demonstrate personal bias or prejudice," and denied the motion as void. Footnote 1 summarizes Rule 3(G): filers who use generative AI must disclose that use and certify that they checked the accuracy of AI-assisted content, and the rule allows sanctions for failure to disclose, including dismissal of the case, document, or pleading without prejudice. No monetary sanction is described.
Why does State v. Stroup matter for law firms using AI?
This matter reached the Montana Supreme Court as a motion to disqualify the trial judge, not as an appeal from a sanction. The defendant argued that Judge Larson’s response to his counsel’s filing (vacating the trial date, rejecting all defense filings, and describing counsel’s “inept use of GenAI”) showed personal bias. Chief Justice Swanson first treated the defendant’s petition for rehearing as curing a missing affidavit and certificate of good faith, then denied the motion: a judge’s choice “to impose sanctions of a kind permitted under Local Rule 3(G)” is not evidence of personal bias, and rulings that can be addressed on appeal cannot support disqualification under section 3-1-805, MCA.
In a parallel motion in State v. Bolich, decided March 27, 2026, the Supreme Court likewise declined to disqualify Judge Larson. As that order recounts the motion, the judge rejected several defense filings, including pretrial motions, after taking judicial notice of an allegation in another case that defense counsel had used generative AI without the required disclosure. The order says any error in rejecting the motions “can be raised on appeal” or by the district court’s ruling on the refiled motions.
Rule 3(G) of the Fourth Judicial District’s rules of practice is one of several Montana district rules requiring disclosure of generative AI use in filings; the Montana state page describes them, and the tracker has its own entry for Rule 3(G).
Implications for your firm
Operational steps a firm reading this case may wish to consider documenting. Strategic and rule-application calls belong to your firm's attorneys.
- Montana's Fourth Judicial District requires disclosure and an accuracy certification for filings prepared with generative AI, and the Supreme Court treated rejection of filings as a sanction that rule permits. Firms with Montana district court matters may wish to consider confirming each district's AI-disclosure rule before filing, with the application to any particular matter left to counsel.
- According to the defendant's allegations, the trial judge took judicial notice of the same lawyer's filings in other cases. Firms documenting AI-use procedures may wish to consider that a disclosure lapse in one matter can draw scrutiny of the lawyer's filings in others before the same judge.
Sources
Primary sources
- The Fourth Judicial District Court's orders in State v. Stroup (DC-24-575), including the March 13, 2026 Order of Rejection, and the similar orders in the two other cases the Supreme Court mentions are not online; their dates, terms and wording are taken from the Montana Supreme Court's account of the defendant's allegations.
- Whether the defense filings were in fact prepared with generative AI is not found by any court in the sources reviewed; the Supreme Court says the defendant 'implies' it.