It is unusual for the Federal Circuit to apply the doctrine of Chevron deference to patent law, but a recent decision is noteworthy—and fractured.

The Chevron deference doctrine, based on the U.S. Supreme Court case of Chevron, U.S.A. v. Natural Resources Defense Council, 467 U.S. 837 (1984) requires a federal court to defer to a federal agency’s interpretation of a federal statute in its area of expertise. The doctrine can only be applied if the language of a federal statute is ambiguous and the agency’s interpretation is reasonable.