Patent misuse is a non-statutory defense to claims of patent infringement, and Congress has enacted 35 U.S.C. § 271(d) to limit its application. To be found guilty of patent misuse, the patentee must act to impermissibly broaden the physical or temporal scope of the patent grant with anti-competitive effect. Further, the misuse must be of the patent-in-suit.

A blocking patent is one that at the time of the license, an objective manufacturer would reasonably believe might be necessary to the practice the technology at issue. Horizontal competitors cannot insulate themselves from misuse liability simply by agreeing to suppress competing technologies before they are fully developed.