As I mentioned in this post back in May, I wasn't entirely sure at the time what my position would be on the question of whether, under U.S. law, a licensee in good standing who wants to initiate a declaratory judgment action for noninfringement should bear the burden of proof on this issue (as the Federal Circuit held in Medtronic Inc. v. Boston Scientific Corp., 695 F.3d 1266 (Fed. Cir. 2012), cert. granted, 133 S. Ct. 2393 (May 20, 2013) (No. 12-1128)), or whether the burden of proving infringement should rest with the declaratory judgment defendant/patent owner. I've come around to the view that the latter view is correct and have signed onto an amicus brief to that effect, authored by Professor John Golden. A copy of the brief can be found here. I am also attaching a copy of the Solicitor General's brief, here, courtesy of Professor Golden.
Whether licensees in good standing should be able to initiate declaratory judgment actions is, in my view, debatable as a matter of policy, but MedImmune clearly holds that they may. Given that, I think it makes little sense to have a different burden of proof depending on whether the challenger is a DJ plaintiff or an infringement defendant. I also think that the proposed rule isn't likely to impose an undue burden on the DJ defendant (say, by asking for a DJ that claims 1-100 are not infringed) because courts can use their local rules, etc. to limit that sort of thing; and the DJ defendant is, after all, asserting that the DJ plaintiff's products fall within the scope of the patent (and, when challenged on this, ought to bear the burden of pointing and substantiating which claims he has in mind).