Prososki v. Regan: Nebraska Supreme Court strikes an appellate brief and refers counsel for discipline over fictitious, allegedly AI-generated citations

The problem

An appeal of a decree of dissolution of marriage reached the Nebraska Supreme Court in which the appellant’s brief, “signed and certified by his counsel,” contained “numerous citations to fake cases, real cases with fake quotations, real cases with mischaracterized holdings, and Nebraska statutes and court rules with fake quotations” (source). The opposing party moved to strike the brief and dismiss the appeal, asserting the errors “are the product of generative artificial intelligence (AI)” (source). The court framed the issue as one of first impression: “This matter presents a novel issue for Nebraska courts: the use of fictitious, potentially AI-generated cases, holdings, and quotations” (source).

What was built

Nothing was “built” in the product sense: this is an AI-governance honest-negative, a court outcome documenting what happens when unverified, allegedly AI-generated legal authority is filed with a court. The artifact under review is a single appellate brief filed by appellant’s counsel, W. Gregory Lake of Plains Legal Group (Omaha), which the court described as “riddled with fabricated citations and quotations” (source). Counsel denied the tool: he “asserted that AI was not used in the drafting of the filed appellate brief,” attributing the fictitious cases and quotations to a screen crack on his laptop and filing the wrong draft (source). The court said it did not matter: “Regardless of whether AI was used in the preparation of Jason’s appellate brief, our analysis in this case is ultimately the same” (source). This file therefore treats AI use as alleged, not established.

The outcome

Brief stricken, appeal dismissed, counsel referred for discipline. In a per curiam opinion filed March 20, 2026 (Prososki v. Regan, 321 Neb. 38, No. S-25-295), the court held: “We now strike the appellant’s brief, dismiss the appellant’s appeal, and refer the appellant’s counsel to the Counsel for Discipline of the Nebraska Supreme Court” (source). It acted “[d]ue to the widespread nature of the fictitious authority” in the brief and “pursuant to our inherent authority” (source). On the merits it reviewed for plain error, found none, and affirmed the district court’s judgment; the cross-appeal was without merit (source).

The court closed with a caution both Nebraska newsrooms reproduced: “AI, like other technological tools, can be a benefit to the legal community, but it must be used with caution and humility” (source, source).

Not a court figure, do not repeat as one: 57 of 63 citations “defective.” The widely circulated “57 of 63” count is the opposing attorney’s, from a February hearing, relayed by WOWT: “the opposing attorney said that of the 63 references Omaha attorney Greg Lake made in his brief, 57 contained some form of defect” (source). It is not a finding in the opinion, which uses “numerous,” “many” and “widespread” and lists example citations in a chart rather than a total (source). The March 20 opinion is also distinct from a later, separate order (reported April 2026) temporarily suspending Lake from practice; that order is not part of this record.

How this was verified

This is a court-origin public record: the trust rests on the signed opinion, not on any party’s confirmation. The opinion was read against the official Nebraska appellate opinion (docId N00013081PUB), held here as a Wayback capture of the opinion PDF, and every quote above was re-verified on 2026-08-07 against that capture. The two independent Nebraska newsrooms that covered the ruling, WOWT and Nebraska Public Media, were captured on the day of the decision and re-checked for the “caution and humility” line and the discipline referral. The one figure that is not the court’s own, the “57 of 63” count, is flagged in the prose above where the reader meets it: it is the opposing attorney’s tally as relayed by WOWT, not a holding, and must not be quoted as one.

Related case files

The clearest parallel is United States v. Hayes, where a court sanctioned a fictitious citation while expressly declining to find that AI was used: as here, the tool is alleged and the analysis holds either way. Ibach v. Stewart is the closest procedural twin, another state supreme court dismissing an appeal over fabricated citations in the brief. Kruse v. Karlen shows the same disposition, an appeal dismissed as a sanction for a brief built on fictitious authority.

Sources

Cited in this case file. Tier 1 = the court’s own signed opinion; Tier 2 = independent newsroom naming the parties. Every quote re-verified on 2026-08-07 against the archived captures held for this file.

1. Nebraska Supreme Court, Prososki v. Regan, 321 Neb. 38, No. S-25-295, per curiam, filed 2026-03-20 (Tier 1, the signed appellate opinion; official copy, docId N00013081PUB, held here as a Wayback capture of the opinion PDF). https://www.nebraska.gov/apps-courts-epub/public/viewOpinion?docId=N00013081PUB
2. WOWT, “Nebraska Supreme Court rules on case involving AI use in court brief,” 2026-03-20 (Tier 2, independent newsroom; source of the opposing attorney’s “57 of 63” count). https://www.wowt.com/2026/03/20/nebraska-supreme-court-rules-case-involving-ai-use-court-brief/
3. Nebraska Public Media, “Nebraska Supreme Court blasts AI-authored court filings, recommends discipline,” 2026-03-20 (Tier 2, independent newsroom). https://nebraskapublicmedia.org/en/news/news-articles/nebraska-supreme-court-blasts-ai-authored-court-filings-recommends-discipline/