The Supreme Court confirmed that patents are entitled to a presumption of validity even when an accused infringer relies on “new” prior art in Microsoft Corp. v. i4i Ltd. Partnership, 564 U.S. ___, 131 S.Ct. 2238 (2011). The decision was very straightforward.

Issued patents are entitled a presumption of validity in federal courts under 35 U.S.C. § 282. This means that a party seeking to invalidate a patent must prove invalidity by clear and convincing evidence, which is a higher standard than the preponderance-of-evidence standard that is required to establish infringement.

The rationale behind this higher standard is that the validity of an issued patent should be presumed because the issued patent has been examined by the United States Patent and Trademark Office (USPTO) prior to issuance. 

The defendant in the Microsoft case argued that this heightened standard should not apply because it had found prior art that, allegedly, had not been considered by the USPTO during the initial examination process. The Supreme Court rejected this argument by determining the intent of Congress in enacting 35 U.S.C. § 282, as evidenced by the wording of the statute, among other things.