Chapman v. Decker
U.S. District Court, Southern District of Illinois · S.D. Ill. · Illinois bar guidance
Conduct
Defense counsel's summary judgment brief cited one case the court said does not exist and three real cases for propositions they do not address.
Consequence
No sanction "at this time" because the errors were immaterial; the court warned that counsel or her firm "can expect to be sanctioned" if it happens again.
Lesson
Here the court said counsel's Rule 11(a) signature certifies the brief's statements are warranted by law, whatever the source of the bad cites, and said counsel had lost its trust.
Verified September 30, 2026
- Citation
- Chapman v. Decker, No. 23-cv-3200-JPG, Memorandum and Order (S.D. Ill. July 10, 2026) (Gilbert, J.), ECF No. 63
- Decided
- July 10, 2026
Summary
John P. Chapman, who filed the case pro se, sued Madison County Jail officers for excessive force, failure to intervene, and failure to provide medical care arising from events in February and March 2022. The defendants moved for summary judgment, arguing among other things that Chapman suffered no more than de minimis injury and that his seizures, which predated the events, could not be causally linked to their conduct. The court was "dismayed that the defendants' brief for this section lists cases that either do not exist or do not say what the defendants say they do." It listed four: Gutierrez v. Kermon, 722 F.3d 1003 (7th Cir. 2013), cited on de minimis injuries but actually about appellate jurisdiction over denials of qualified immunity; Estate of Allen v. City of Chicago, No. 16-cv-8094, 2018 WL 4495982 (N.D. Ill. Sept. 19, 2018), which the court said "does not exist"; and Williams v. Rodriguez, 509 F.3d 392 (7th Cir. 2007), and Houskins v. Sheahan, 549 F.3d 480 (7th Cir. 2008), both cited on causation but, per the court, addressing other issues (an asthma medical-need question and joinder of claims for trial). The order refers to defense counsel as "her" and does not name her.
- AI tool:
- Unidentified (the court observed that "[s]uch phenomena are becoming more frequent in the age of generative artificial intelligence" but held counsel responsible "whether these mistakes are a result of AI or other error"; it made no finding that AI was used)
What did the court warn about?
Judge J. Phil Gilbert declined to sanction defense counsel. The court wrote that "whether these mistakes are a result of AI or other error, counsel's signature under Federal Rule of Civil Procedure 11(a) certifies that the statements in her brief are warranted by existing law; the misstatements listed above clearly are not." "Because the misrepresentations at issue here are immaterial to the Court's decision on the issue in question, the Court declines to sanction counsel at this time." It warned that it "will tolerate no more such sloppiness, giving it the most generous interpretation, or deceit, giving it the worst," and that "[s]hould counsel or her law firm again make such misrepresentations, they can expect to be sanctioned," adding that they "have lost the trust of this Court." On the merits, the court rejected the injury-and-causation argument, granted summary judgment in part and denied it in part, and left excessive-force claims against three officers for trial.
Why does Chapman v. Decker matter for law firms using AI?
Chapman is a warning order, and its reasoning does not depend on how the bad citations were produced. In the section of the defendants’ summary judgment brief on injury and causation, Judge Gilbert found one case that “does not exist” and three real Seventh Circuit decisions cited for propositions they do not address. The court acknowledged that “[s]uch phenomena are becoming more frequent in the age of generative artificial intelligence,” but did not decide whether AI was involved. It placed the responsibility on the signature: under Rule 11(a), counsel certified that the brief’s statements were warranted by existing law, and “the misstatements listed above clearly are not.”
The court declined to sanction because the misrepresentations were “immaterial to the Court’s decision on the issue in question.” The court then rejected the argument on the merits, relying on Hudson v. McMillian and Wilkins v. Gaddy to hold that a jury could find Chapman suffered injuries to his face and head, and on Chapman’s testimony and the timing of his seizures to hold that a jury could find the force caused them. The warning is framed in unusually direct terms: the court “will tolerate no more such sloppiness, giving it the most generous interpretation, or deceit, giving it the worst,” and said counsel had “already wasted the Court’s time chasing down fictitious cases or holdings and have lost the trust of this Court.”
Two features may matter to a firm reading the order. First, the warning runs to “counsel or her law firm,” so the firm, not only the individual lawyer, is on notice in this court. Second, the court said it expected “far better from defense counsel, who has regularly and ably appeared before the Court for decades.” Firms documenting compliance may wish to consider cite-checking that tests each authority against the proposition it is cited for, since three of the four flagged citations were to real cases.
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.
- Verify that each cited case addresses the proposition it is cited for. Three of the four authorities the court flagged are real Seventh Circuit decisions cited for points they do not discuss.
- Document citation review for the firm, not just the individual lawyer. The court's warning covers both counsel 'or her law firm' if such misrepresentations recur.
- Consider that experience did not change the analysis. The court noted that defense counsel 'has regularly and ably appeared before the Court for decades' and still found the misstatements unwarranted by existing law.