Today, the Supreme Court confirmed that parties challenging the validity of a patent have the burden to prove invalidity by clear and convincing evidence. Justice Sotomayor delivered the unanimous opinion for the Court in its decision in Microsoft Corp. v. i4i Limited Partnership (No. 10-290), which affirmed the Federal Circuit. Justice Breyer filed a concurring opinion, and Justice Thomas filed an opinion concurring in judgment. Chief Justice Roberts took no part in the decision.
By statute (35 U.S.C. § 282), patents are presumed valid, based, in part, on the deference shown to the Patent Office in examining patents. In the underlying case, Microsoft challenged the validity of the patent using a reference never considered by the Patent Office when examining the patent. Microsoft argued that the presumption of validity did not mean that it needed to prove invalidity by clear and convincing evidence, especially in these circumstances. Both the district court and the Federal Circuit disagreed, finding under long-established precedent that those challenging the validity of a patent must prove invalidity by clear and convincing evidence in all circumstances.
Microsoft’s Arguments For a Preponderance of the Evidence standard
At the Supreme Court, Microsoft argued that the Court should adopt one of two standards, either (1) accused infringers need only prove invalidity by a preponderance of evidence or (2) a hybrid approach where accused infringers need to prove invalidity by clear and convincing evidence for those references considered by the Patent Office but only by a preponderance of the evidence for anything else. The Supreme Court strongly rejected both approaches and affirmed the clear and convincing standard in all circumstances.
The Supreme Court’s Analysis
Tracing the history of patent law in the United States, the Court noted that it had previously considered the standard of proof in its decision in Radio Corp. of America v. Radio Engineering Laboratories, Inc., 293 U.S. 1 (1934). In that decision, Justice Cardozo stated that “there is a presumption of validity, a presumption not to be overthrown except by clear and cogent evidence.” This common-law understanding was well-rooted by the time that Congress enacted § 282, which declared that patents are presumed valid.
The Court also found persuasive how Congress reacted to the courts on this point. In 1984, the Federal Circuit recognized the clear and convincing standard of proof in its decision in American Hoist & Derrick Co. v. Sowa & Sons, Inc., 725 F.2d 1350 (Fed. Cir. 1984), and, in the nearly thirty years since that decision, consistently reaffirmed this standard of proof. Despite amending the patent act numerous times since the American Hoist decision, Congress never expressed disapproval with the Federal Circuit’s decisions, which indicated to the Court that Congress agreed with this standard.