On March 21, 2017, the U.S. Supreme Court ruled that patent-infringement defendants may not assert “laches” as a defense to unreasonably delayed infringement suits. The decision was a setback for WLF, which filed a brief urging the Court to accept the unanimous view of the federal appeals courts that application of laches is permissible in appropriate circumstances—e.g., when the plaintiff’s unreasonable delay has unfairly prejudiced the defendant. Federal patent law explicitly bars a patent holder from recovering damages for patent infringement that occurred more than six years before the date on which suit was filed. This case asked the Court to decide whether alleged infringers may also seek to bar damages for infringement that occurred within the six-year window, by invoking laches. Rejecting WLF’s arguments, the Court held that Congress implicitly abolished the laches defense when it adopted a six-year statute of limitations.