
A recent Third Circuit decision underscores a growing risk for practitioners: relying on AI-generated research without verification can damage both a case and counsel’s credibility.
In McCarthy v. DEA, a Pennsylvania attorney submitted a brief relying on AI-generated summaries of eight DEA adjudications to argue the agency had acted inconsistently. The summaries—provided by a non-attorney—were incorporated without reviewing the underlying decisions. Seven were “riddled with factual and legal inaccuracies.” The eighth did not exist.
Although the attorney later acknowledged the issue, he initially characterized the errors as “minor discrepancies” and did not verify the cited authorities until ordered to do so by the Court. His reply brief introduced additional inaccuracies.
The Third Circuit found multiple violations of Pennsylvania ethical standards, noting that the attorney wasted the resources of both the Court and the DEA and harmed his own credibility. Still, the majority stopped short of imposing monetary sanctions. Citing his belated corrections and “sincere contrition,” the Court issued only a reprimand, observing that it had not yet clearly articulated expectations regarding AI use.
A strong dissent urged that the egregious conduct of the attorney was more than a mere mistake. The dissent cited myriad cases across the country, including Park v. Kim, wherein the Second Circuit emphasized that a rule about artificial intelligence use “is not necessary to inform a licensed attorney … that she must ensure that her submissions to the Court are accurate.” The client’s case was dismissed for numerous violations of Federal Rule 11, and the attorney was referred to the Court’s Grievance Panel.
Agreeing with the Second Circuit in Kim, the dissent in McCarthy concluded with
But punishing an attorney for failure to verify information obtained from AI is consistent with the standard to which attorneys historically have been held. No forewarning is necessary when it is clear what standard the attorney was required to follow. The ethical practice of the law is innate in the responsibilities of each practicing attorney. It needs no reminder as each case is accepted and resolved. The takeaway is straightforward: courts may differ on sanctions, but not on the underlying duty. Verification is not optional.
The takeaway is straightforward: courts may differ on sanctions, but not on the underlying duty. Verification is not optional.
And while McCarthy reflects restraint, most courts considering similar conduct have not been as forgiving—a trend that is likely to continue.





