Several music companies sued Cox Communications, arguing that the ISP should be held liable for copyright infringement committed by some of its subscribers. The Court of Appeals for the Fourth Circuit agreed, adopting a “material contribution” standard for contributory copyright liability (a rule for when service providers can be held liable for the actions of users). The lower court said that providing a service that could be used for infringement is enough to create liability when a customer infringes.

The Fourth Circuit’s rule threatened devastating consequences for the public. Terminating an ISP account doesn’t just affect a person accused of unauthorized file sharing—it cuts off entire households, schools, libraries, or businesses that share an internet connection.

• Public libraries, which provide internet access to millions of Americans who lack it at home, could lose essential service.
• Universities, hospitals, and local governments could see internet access for whole communities disrupted.
• Households—especially in low-income and communities of color, which disproportionately share broadband connections with other people—would face collective punishment for the alleged actions of a single user.

With more than a third of Americans having only one or no broadband provider, many users would have no way to reconnect once cut off. And given how essential internet access is for education, employment, healthcare, and civic participation, the consequences of termination are severe and disproportionate.

EFF filed an amicus brief asking the Court to reject the Fourth Circuit’s unfounded “material contribution” test, reaffirm that patent law provides the right framework for secondary liability, and make clear that the Constitution requires copyright to serve the public good. EFF asked the Court to ensure that copyright enforcement doesn’t jeopardize the internet access on which participation in modern life depends.

On March 25, 2026, the Supreme Court reversed the Fourth Circuit. In an opinion by Justice Thomas, the Court rejected the Fourth Circuit's liability theory. The Court agreed with the approach of EFF's amicus brief, holding that secondary copyright liability should "track" the same rules as patent law, for actively inducing infringement or contributory infringement. Here, Cox didn't actively induce its customers to infringe—to the contrary, it took active steps to discourage and prevent infringement. And the internet services Cox provided to its customers are overwhelmingly used for noninfringing purposes. Thus, the Supreme Court reversed the Fourth Circuit decision, and held that Cox was not liable in this case.

EFF's blog post about the Supreme Court opinion is here.