Two sets of authors sued Anthropic and Meta in San Francisco for copyright infringement, arguing that the companies had pirated their works to train their LLMs. Everyone agreed that a key question was whether fair use allowed it, and in both cases, the courts looked at the fair use issue before dealing with other aspects of the cases. Even though the facts in both cases were very similar, last week, two judges in the same court wrote opinions, coming to very different conclusions. How can that happen? Is fair use broken?