Correct. The long version: The plaintiff in a patent case is usually the patent-holder, who is seeking damages for infringement. In those cases, the patent-holder-plaintiff already had the burden of proof. In this case, the (potentially infringing) plaintiff is seeking protection from patent infringement lawsuits by suing the patent holder, requiring the (patent holder) defendant to prove that the patents are valid and/or that the plaintiff infringes the patents. Normally (and the appeals court found), the plaintiff would have the burden of proof. According to the appellate ruling, the plaintiff (potential infringer, seeking protection) would have to prove that they were not infringing, or prove that the patents were invalid. The Supreme Court reaffirmed the lower court ruling: The patent holder, whether plaintiff or defendant, must prove that the other party (plaintiff or defendant) infringed the patents, and that the patents are valid.