TL;DR: On June 3, 2026, the Ninth Circuit issued a published, precedential order in LNU, et al. v. Blanche sanctioning two immigration-brief authors for briefs that contained AI-generated fabrications, misattributed quotes, and gross misrepresentations of real cases. The court held that sanctions attach at the moment of signing and filing, not merely for using AI, and imposed monetary penalties, a six-month suspension from Ninth Circuit practice for the attorneys, and a firm-wide obligation to disclose AI use in future filings for a two-year period. The decision is a clear signal that trial lawyers must verify AI outputs and maintain candor in every stage of litigation, with concrete procedural steps to reduce risk in appellate and trial work.
What happened
In LNU, et al. v. Blanche, No. 24-4790 (9th Cir. 2026), the Ninth Circuit addressed allegations that two attorneys filed briefs for which multiple authorities did not exist, quotations were misattributed, and real-court authorities were grossly misrepresented, with the basis traced to generative AI hallucinations. The panel concluded that the misconduct was not merely the product of using AI, but of signing and filing briefs that contained fabricated or misrepresented authorities. The court imposed monetary sanctions, suspended the attorneys from Ninth Circuit practice for six months, and required both the attorneys and their firm to implement new disclosure and verification measures for AI use in future filings. The opinion emphasizes that the duty of candor applies at every stage of litigation, and that AI-generated content must be carefully checked and personally reviewed by the signing attorney before filing. The published order was issued June 3, 2026, and the court’s analysis repeatedly ties accountability to the act of signing and submitting documents, not merely to the initial research process. (law.justia.com)
The court also ordered that moving forward, the law firm must include a statement in all future filings addressing whether generative AI was used, identifying the tool, and certifying that the signing attorney personally reviewed the material and that citations and quotations refer to existing authorities. The sanctions and disclosure requirements are set to remain in effect for two years from the date of the order. While the ruling does not prohibit the use of AI tools outright, it makes clear that unchecked AI outputs and a lack of candor about AI involvement can trigger serious disciplinary consequences. The decision is now part of Ninth Circuit precedent on professional conduct in the age of AI-assisted drafting. (cdn.ca9.uscourts.gov)
Why this matters for trial attorneys
This decision is timely and consequential for trial teams across the United States, because it translates a courtroom ethics standard into concrete practice rules for AI-assisted advocacy. First, it clarifies that the duty of candor applies to every filing, including appellate briefs and trial-related submissions, and that misrepresentations or fabrications—whether produced by humans or by AI—are subject to sanction when signed and filed. Second, the ruling makes explicit that the act of signing a document triggers potential discipline if the content contains fabricated authorities or material misrepresentations, underscoring the importance of thorough verification before submission. Third, the two-year AI-disclosure requirement creates a formal obligation that will require firms to adopt internal policies for documenting AI usage in research and writing, as well as training on how to vet AI outputs for accuracy and reliability. These are practical changes that trial teams can operationalize now through policy updates, training, and enhanced quality-control checks. (law.justia.com)
The LNU decision aligns with growing attention to AI risk in litigation, including the need for verifiable sourcing, prompt verification, and attorney accountability in the era of AI-assisted drafting. While this ruling originates from the Ninth Circuit, its message resonates nationally: AI tools can accelerate work, but courts will hold counsel to strict standards of accuracy and candor when presenting authorities. For trial teams handling appellate briefs, motions, or any submission that cites caselaw, the decision reinforces that independent verification and honest disclosure are not optional extras but essential professional responsibilities. (cdn.ca9.uscourts.gov)
Practical steps for trial teams now
- Implement a mandatory AI-disclosure policy. Require every brief or motion to include a brief statement disclosing whether AI tools were used, the specific tool(s) employed, and a certification by the signing attorney that all cited authorities are real and accurately quoted. This policy should mirror the dual emphasis on transparency and personal responsibility highlighted by the LNU ruling.
- Institute a rigorous verification checklist. Create a pre-signing checklist that requires each citation to be cross-checked against the cited authority, with direct confirmation from the responsible attorney that the authority exists and the quotation accurately reflects the source. Consider a senior reviewer or a secondary attorney to verify AI-derived outputs before filing.
- Train teams on AI hallucinations and bias. Use practical, scenario-based training to illustrate how AI can generate fabrications or misstate holdings, and teach how to spot common hallucination patterns. The Ninth Circuit’s sanctions order underscores that even sophisticated AI can produce unreliable outputs if not actively checked.
- Align e-discovery and trial prep with a robust governance framework. Update discovery protocols to incorporate AI-use controls, including the handling of generated summaries, citations, and exhibits. Ensure protective orders and work-product protections cover AI prompts and outputs where appropriate, while preserving the duty of candor.
- Budget for risk management and sanctions exposure. Recognize that AI-assisted work can carry new risks and potential sanctions. Build project budgets that account for extra attorney time spent on verification, quality control, and compliance training.
- Leverage Objection Academy for focused practice. Irrespective of the case type, trial teams can benefit from objection-focused drills and evidence-training programs. Objection Academy’s training can help teams refine how to handle AI-generated content in court, practice effective objections to questionable outputs, and strengthen overall trial-readiness. The discipline in LNU reinforces the value of precise, evidence-based advocacy and controlled use of AI in litigation. (law.justia.com)
Objection Academy in practice
For litigation teams seeking practical, evidence-centered training, Objection Academy offers scenario-driven drills aimed at sharpening objections, impeachment, and the application of the Federal Rules of Evidence in real courtroom contexts. The June 2026 LNU ruling underscores the risk of AI-generated content slipping into signatures and submissions, and Objection Academy’s emphasis on disciplined practice can help teams build muscle memory for checking sources, preserving privilege concerns, and maintaining the integrity of trial materials even when AI tools are in use. Integrating Objection Academy into the firm’s ongoing training program can be a concrete step toward meeting the higher standard set by the Ninth Circuit decision. (law.justia.com)
What to watch next
- Expect continued refinement of AI-use discipline standards in other circuits. While LNU v. Blanche is a Ninth Circuit decision, other circuits may issue comparable guidance on sanctions, candor, and AI disclosure requirements in the near term.
- Monitor additional developments in professional conduct rules and ethics opinions addressing AI in litigation. Courts, bar associations, and training organizations are actively shaping best practices for AI-assisted advocacy.
- Stay tuned for firm-wide policy templates and checklists that reflect the LNU approach. Law firms can adapt the core lessons from this ruling into standardized guidelines for all litigators, reducing risk and promoting courtroom credibility.
Sources:
- LNU, et al. v. Blanche, No. 24-4790 (9th Cir. 2026), published June 3, 2026. The Ninth Circuit sanction order and its reasoning are documented in the court’s opinion and accompanying summaries. (cdn.ca9.uscourts.gov)
- Medal et al. v. Amazon.com Services LLC, WD Wash. 2026, and related orders discussing Rule 502(d) protections and AI in discovery (contextual background on AI-related disputes in federal courts). (law.justia.com)
- First Choice Women’s Resource Centers v. Davenport, SCOTUS decision (April 29, 2026) and related coverage, illustrating evolving federal court treatment of donor-subpoena challenges (for broader context on how high courts are engaging with AI-affected litigation issues, though not the focus of this piece). (law.cornell.edu)
Note: This timely development commentary focuses on a concrete, recent court action with clear implications for trial teams, supported by publicly accessible court documents and reputable legal summaries.