Maintaining the Clear and Convincing Evidence Standard for Patent Invalidity Challenges in Microsoft Corp. V. I4i Limited Partnership, 131 S. Ct. 2238 (2011)‪.‬

The term "burden of proof" is one of the "slipperiest members of the family of legal terms," and the correct standard of proof when challenging the validity of a patent is no exception. (l) Section 282 of the Patent Act states that "[a] patent shall be presumed valid" and that "[t]he burden of establishing invalidity of a patent ... shall rest on the party asserting such invalidity." (2) Eighteen years before the Act's codification in 1952, the Supreme Court held that the presumption of validity must be overcome by clear and convincing evidence. (3) In the years following the Patent Act's enactment, the Federal Circuit similarly interpreted Section 282 to require a defendant seeking to overcome this presumption to prove invalidity by clear and convincing evidence. (4) The clear and convincing evidentiary standard is higher than the "preponderance of the evidence" standard commonly used in civil cases, but lower than the "beyond a reasonable doubt" standard for criminal cases. (5) The main rationale for requiring a higher evidentiary standard to prove the invalidity of patents is deference to the decision of the United States Patent and Trademark Office (PTO) to grant the patent in the first place after considering any relevant "prior art." (6) Prior art is defined as the knowledge of, usage of, patent on, or description relating to an invention already in existence before the invention described in the patent application. (7) As part of its duties, the PTO must search for any relevant prior art and consider any prior art relating to the subject matter of the claimed invention before granting a patent. (8) Last Term, in Microsoft Corp. v. i4i Limited Partnership, the Supreme Court held that the clear and convincing evidence standard applies to all invalidity challenges to patents--even when the patent's prior art has not been considered by the PTO. (9) Purporting to defer to Congress's intent as expressed in the Patent Act, the Court found that because the presumption of patent validity articulated in Section 282 of the Patent Act already had a common law meaning at the time the Act was passed, Congress intended the clear and convincing standard to apply to all challenges based on a patent's invalidity. (10) In so doing, however, the Court ignored the fundamental logic behind the presumption, thereby setting the standard for proving patent invalidity higher than Congress actually intended for patents whose prior art was never reviewed by the PTO. Although this mistaken decision might decrease uncertainty about the burden of proof for invalidity defenses, the Court's opinion clears the way for holders of bad patents to stifle innovation and business growth.