The equitable defense of laches bars a plaintiff’s claim if the plaintiff has unreasonably delayed filing suit to the prejudice of the defendant. In Petrella v. Metro-Goldwyn-Mayer, Inc., the Supreme Court ruled that no such defense was available in a copyright action. Today, the Supreme Court extended Petrella to patent cases seeking damages for infringement, overturning 25 years of contrary Federal Circuit precedent.
In the majority opinion, which was authored by Justice Alito, the Court held that the Patent Act’s six-year limitations period reflects Congress’s judgment as to the appropriate timeframe for patent infringement damages actions. Laches, the Court held, is a gap filling equitable defense, so it serves no function when Congress has specified the applicable limitations period.
Justice Breyer dissented. In his view, despite the statute of limitations, there remains a gap to be filled by laches because, unlike other limitations periods, the Patent Act’s six-year bar merely prohibits a plaintiff from collecting damages from wrongful acts that are more than six years old—as opposed to foreclosing claims entirely if they could have been brought more than six years earlier. Justice Breyer would have recognized a laches defense, to prevent a plaintiff from intentionally delaying the filing of an action until a time when the six-year lookback period would contain greater damages.
The Court’s decision does not preclude an accused patent infringer from interposing a defense of equitable estoppel, if the alleged infringer relied on indications from the patent holder that claims of infringement would not be pursued.