Third Circuit Declines Fair Use Defense for AI Training on Westlaw Headnotes

The Third Circuit’s ruling affirms that Westlaw’s editorial headnotes are subject to copyright and rejects a defense that their use for training AI models qualified as fair use. The court held that the headnotes’ derivation from underlying case law conferred copyright protection, and that the AI‑training activity did not meet the transformative or qualitative tests of fair use. The decision signals a higher bar for legal‑research AI tools that rely on proprietary headnotes, prompting firms to reassess data‑sourcing models and to document compliance frameworks. Firms should audit their AI‑training datasets for copyrighted content, consider licensing agreements with Westlaw, and monitor subsequent circuits for similar challenges. The ruling may also spur the industry to develop open‑source or white‑label headnote alternatives to meet the growing demand for AI‑enhanced legal research.