The dispute
Thomson Reuters alleged that ROSS Intelligence used material connected to Westlaw headnotes in the development of a competing legal research system. Judicial opinions themselves and editorial headnotes present different copyright questions, so descriptions that reduce the case to "AI trained on court cases" miss the central distinction.
The 2025 decision
The District of Delaware revisited summary judgment issues and ruled for Thomson Reuters on significant copyright questions, including fair use as addressed in the decision. The procedural history and later appellate activity matter; readers should check the docket before treating any case note as the final word.
What organisations should learn
- Identify the provenance and licence for training, retrieval and evaluation data.
- Separate public-domain source material from copyrighted editorial additions.
- Document whether a use substitutes for the source product or serves a different purpose.
- Track the procedural status of any case used in a risk assessment.
- Do not generalise a fact-specific copyright ruling into a universal rule for every model or jurisdiction.
Why it belongs in an AI lawsuits tracker
The case is valuable because it connects legal AI product design to data governance and competitive purpose. It does not determine whether a judge may use a drafting assistant, nor does it resolve confidentiality obligations for uploaded case files. Those questions need their own sources and controls.
Compare the professional-verification issue in Mata v. Avianca and the broader AI lawsuits map.