Lichfield v. Kubler

What did the court warn about?

In a published opinion by Judge Federico, the panel affirmed the dismissal. It held that the Opening Brief "failed to fully comply with Rule 46.5," the Tenth Circuit rule under which a filer certifies a reasonable inquiry that the issues are warranted by existing law, and that filing it was "conduct sanctionable at our discretion" under 10th Cir. R. 46.5(C). Comparing Amarsingh v. Frontier Airlines ($1,000 and a disciplinary referral for a brief citing seven nonexistent cases), the panel found "the errors are not as egregious" and the brief "had significantly fewer errors," while noting that generative AI "is no longer a novel tool." It was "further concerned" that the reply brief "did not appropriately remedy the misstatements of law," and said a correction "should not have taken questioning at argument." It concluded: "The missteps in this case do not merit sanctions." It cautioned that generative AI's "use may result in hallucinated falsities" and that counsel "is responsible for ensuring briefs and representations made to the court are warranted by the law and supported by the record, no matter the technology used to create them."

Why does Lichfield v. Kubler matter for law firms using AI?

Lichfield is a published Tenth Circuit opinion that declines sanctions but sets out, in its own words, what the court expects when a brief contains fabricated authority. The panel read its Rule 46.5 certification to require that “a bare-minimum reasonable inquiry will ensure legal authorities cited in papers submitted to the court actually exist, and the quotations or propositions attributed to them also exist,” and held that the Opening Brief “failed to fully comply” with the rule. That made the filing sanctionable in the court’s discretion, and the panel listed sanctions its rules allow, which “may include” dismissal of the appeal, monetary payments, initiation of disciplinary proceedings, and an order to pay the opposing party’s reasonable expenses.

The court calibrated against its February 2026 decision in Amarsingh v. Frontier Airlines, where an attorney litigating pro se whose brief cited seven nonexistent cases was ordered to pay $1,000 toward opposing counsel’s fees and costs and the matter was referred to the relevant disciplinary body. Here there was one nonexistent authority and two mischaracterized cases, so “the errors are not as egregious.” The AI attribution is expressly an assumption: “we assume the use of generative artificial intelligence led to the misrepresentations of legal authority.” The panel’s concern was as much with the response to the errors as with the errors themselves. The reply acknowledged “several citation errors” and then turned to the opponent’s supposed mischaracterizations, and a Notice of Errata came only after questioning at oral argument. “Submission of a brief containing fabricated or hallucinated citations is a divergence from the standards expected of attorneys appearing before this court. Any such error should be corrected explicitly and without prompting.”

Firms documenting compliance may wish to consider that this panel treated the timing and completeness of the correction as a factor in its analysis, alongside the number of errors. An explicit correction made without prompting, rather than a passing concession in a reply, is the course the opinion describes.