Kohls v. Ellison: a court throws out a Stanford misinformation expert's declaration after GPT-4o invented its citations

The problem

Christopher Kohls and Mary Franson challenged a Minnesota statute restricting AI-generated “deepfakes” in elections, and moved for a preliminary injunction on First Amendment grounds. To oppose that motion, Minnesota Attorney General Keith Ellison submitted two expert declarations — one from University of Washington professor Jevin West, and one from Stanford professor Jeff Hancock, Director of the Stanford Social Media Lab and a credentialed expert on AI and misinformation. The plaintiffs moved to exclude both, and specifically “alleged that Professor Hancock included fabricated material in his declaration.”

What was built

After the plaintiffs’ motion, the Attorney General’s office contacted Hancock, “who subsequently admitted that his declaration inadvertently included citations to two non-existent academic articles, and incorrectly cited the authors of a third article.” As the order records, “[t]hese errors apparently originated from Professor Hancock’s use of GPT-4o—a generative AI tool—in drafting his declaration,” and “GPT-4o provided Professor Hancock with fake citations to academic articles, which Professor Hancock failed to verify before including them in his declaration.” The court underlined the irony: “Professor Hancock, a credentialed expert on the dangers of AI and misinformation, has fallen victim to the siren call of relying too heavily on AI—in a case that revolves around the dangers of AI, no less.”

The outcome

Judge Laura M. Provinzino held that “the Court cannot accept false statements—innocent or not—in an expert’s declaration submitted under penalty of perjury,” and that Hancock’s “citation to fake, AI-generated sources in his declaration … shatters his credibility with this Court.” The court therefore ordered that “Plaintiffs’ Motion to Exclude Expert Testimony (ECF No. 29) is GRANTED IN PART AND DENIED IN PART. The motion is granted as to the Hancock Declaration and denied as to the West Declaration.” Because it “declines to consider Professor Hancock’s testimony in deciding Plaintiffs’ preliminary-injunction motion,” the court also held that “Defendants’ Motion for Leave to File an Amended Expert Declaration (ECF No. 34) is DENIED AS MOOT” — the state could not repair the AI-tainted evidence. Notably, this order imposed no monetary sanction: the AI failure cost the party its expert evidence, not a fine. (The order observes in general terms that “[t]he consequences of citing fake, AI-generated sources for attorneys and litigants are steep,” citing Mata v. Avianca and other cases.)

Path to green

Every fact here is stated by an independent federal court in a signed, publicly filed order that is byte-identical to its Wayback capture (CDX digest KAG3WUT5VJN2HU6D6LZ3MD4E6PDYR3DN, archived 2025-01-14) — so the facts need no client-confirmation call to be true. There is no dollar figure to confirm; this is an evidentiary exclusion. The human step that would earn a green badge is confirming the litigation’s downstream posture: the court later denied the preliminary injunction and the case went to the Eighth Circuit (No. 25-1300), and no party has been shown to have re-offered the excluded declaration.