Gavel iconContinuing with our series reporting on the recent U.S. Supreme Court decisions, today we will decipher the impact of the second patent case, Commil v. Cisco, and the claim of “induced infringement.”

Belief in Patent Invalidity is not a Defense

The Commil v. Cisco decision involved the issue of what knowledge is required by a defendant in a claim of induced patent infringement. Briefly, a party can be liable for directly infringing the patent of another, where it utilizes patented matter of another without authorization, or by inducing a third party to infringe a patent of another. Induced infringement often involves situations where a party may simply provide the means to third-parties and their use of those means result in infringement of a patent.

Facts of the Case

In Commil, plaintiff claimed that Cisco both directly infringed its networking communications patent and induced infringement of that patent by virtue of sales of products to others that resulted in infringement of the patent. Cisco sought a reexamination of the patent and it was held valid. In the infringement trial, Cisco argued that it could not be liable for induced infringement because it had a good faith belief the Commil patent was invalid. The district court rejected this argument and would not allow Cisco to assert same to the jury, precluding this as a defense to the claims. The jury ultimately awarded a $60 million verdict, finding both direct and induced infringement by Cisco. Cisco appealed to the Federal Circuit arguing the district court erred when it did not permit Cisco to present evidence of its good faith belief that the patent was invalid as a defense to Commil’s induced infringement claims. The Federal Circuit agreed with Cisco, indicating that a good faith belief in invalidity of a patent could be a defense to a claim of induced infringement.

U.S. Supreme Court Decision

The Supreme Court reversed the Federal Circuit, clearly stating that a good faith belief in invalidity of a patent is not a plausible defense to a claim of induced infringement. The Court considered that the issues of patent infringement and liability for infringement are different issues. The Court noted “invalidity is not a defense to infringement, it is a defense to liability.” Thus, the validity question does not impact infringement and therefore a good faith belief a patent is invalid is not a defense to an infringement claim.


By taking away a defense to induced infringement claims, Commil appears to be a victory for patent owners, including those that might be considered “trolls.” While the Commil Court went to lengths to describe its decision as not troll-friendly, how this plays out in the courts will be an issue to watch.