Executive Summary

Dilution is a trademark law claim in the Lanham Act that provides greater protection to famous marks. Recently, copyright stakeholders have latched on to a new theory of copyright “dilution” to expand the scope of cognizable market harms posed to their works when courts analyze Factor 4 of fair use. Under this newfound theory, the non-infringing works of expression generated by an AI model should be treated as cognizable market harm, or “dilution,” simply because they are in the same genre—an uncopyrightable idea or method—as the unlicensed copyrighted works used to train the AI model. Under this tautology, if the datasets used to train the AI model contained romance novels or music, every non-infringing romance novel or music people write using the AI model is copyright dilution. Indeed, if the datasets contained any other genre, all works in that genre created with the AI model is copyright dilution. Even though copyrights have never encompassed, let alone imposed liability on, the non-infringing works of others, copyright dilution aims to do just. As one federal judge concluded in dicta, it is generally illegal for AI developers to use unlicensed works to train their models. Why? Copyright dilution.

Yet, copyright dilution is a recent concept that has been subject to little discussion, much less scrutiny. It is not in the Copyright Act. And, until 2025, it had never been mentioned in any federal court decision. As the Copyright Office conceded in endorsing copyright dilution, it is “uncharted territory."

But copyright dilution is not only unprecedented, it is also unconstitutional. This Essay is one of the first in legal scholarship to examine the constitutionality of expanding the scope of copyright, in the fair use analysis, to include completely non-infringing works of others. Such a radical expansion of copyright is problematic. It stretches copyright beyond the permissible bounds in the Copyright Clause, which limits the grant of copyright, or exclusive rights, to authors in only “their respective writings.” Authors cannot own entire genres, and the non-infringing works of others are not theirs. Moreover, because copyright dilution alters the traditional contours of copyright, both fair use and the idea-expression dichotomy, it must be subject to strict scrutiny under the First Amendment. Copyright dilution fails. As the Supreme Court recognized, “Mere speculation of harm does not constitute a compelling state interest.” Indeed, the only federal court to embrace copyright dilution as a theory ultimately concluded that the plaintiffs had failed to present anything other than “speculation.” And, by singling out the non-infringing works of only one class of creators—people who use AI tools to create—for disfavored treatment as dilution, copyright dilution constitutes impermissible viewpoint discrimination. Such targeting of the non-infringing expression of only people who use AI—and no others—is viewpoint discrimination.