Appeals court rules ROSS copying of Westlaw was not fair use

Here's a sentence you don't get to write often in this business: an appeals court looked at an AI company's fair use defense and said, flatly, no.

The case is Thomson Reuters v. ROSS, and it's been grinding through the courts since May 2020, when Thomson Reuters sued after ROSS used its Westlaw headnotes to train an AI legal research platform. The district court in Delaware sided with Thomson Reuters. ROSS appealed. The Third Circuit just affirmed — and in doing so, became the first appeals court to rule that this kind of unauthorized copying by an AI company is not protected by fair use.

That "first" matters more than any single headnote dispute. Fair use arguments from AI companies have leaned hard on the idea that training data markets don't really exist yet — that nobody's losing money because nobody was ever going to get paid for this in the first place. The Third Circuit didn't buy it. The court noted that the licensing market for AI training is, in its words, "rapidly developing." That's not a stray observation — it's the hinge the whole ruling turns on, and it's the line AAP CEO Maria Pallante called out directly, saying the decision "supports the premise that a robust licensing market among developers and rightsholders is essential to achieving sustainable and ethical progress in AI technology."

Authors Guild CEO Mary Rasenberger put it in plainer terms: the ruling "vindicates copyright law" and "clarifies that one cannot steal someone else's works to train an AI system that displaces the very works the AI was trained on." She's right that this cuts at something specific — AI companies "try to minimize or flatly deny" that a licensing market exists in their fair use arguments, and now there's appellate precedent saying otherwise.

What this means for you: if you've been wondering whether your backlist, your training-data complaints, or your publisher's licensing negotiations have any legal teeth, this is the teeth. It's not your case and it's not your payout — but it's the precedent your agent, your publisher, and your Guild will be citing the next time an AI company claims your work was fair game.

This week, do two things. First, if you've gotten any licensing inquiry or notice about AI training use of your work, don't let it sit in your inbox — this ruling just made those conversations worth having. Second, watch for the Authors Guild's next statement on how this precedent applies beyond the legal-research niche ROSS operated in. The language here — "rapidly developing" licensing market — is about to show up in a lot of other briefs. Make sure it shows up in arguments made on your behalf, too.