The Federal Circuit recently decided in Commil USA, LLC v. Cisco Systems, Inc. that a good faith belief that a patent is invalid may negate the intent required for an induced infringement case (i.e., a case where the plaintiff is accused not of directly infringing, but rather of inducing others to infringe a patent).
Practically speaking, this new decision reinforces the importance of obtaining opinions of counsel. An opinion letter is strong evidence to demonstrate a lack of intent in an inducement case, whether the opinion is one of noninfringement or, as this latest decision makes clear, one based on invalidity.