The Supreme Court’s eBay decision creates enormous uncertainty about whether the owner of a valid patent has an exclusive right in the face of actual infringement. The Court’s “traditional equitable” criteria for an injunction fail to consider the context where injunctive relief may be warranted: namely, litigation dealing with patents where a jury or court has found the in-suit patent to be valid and infringed and where, barring an injunction, there will be post-trial infringing uses by the defendant. Specifically, it is highly unlikely that a patent holder can show that it will be irreparably harmed or not be made whole, at least in principle, by monetary compensation. In decisions subsequent to eBay, the Federal Circuit has added to the uncertainty by equivocating about whether the holder of a valid patent is entitled to monetary compensation for infringing uses of its patent between the end of a trial and the expiration of the patent if an injunction is not issued.

I suggest a simple two-part rule: the prevailing plaintiff is entitled to an injunction unless the infringer can persuade the district court that an injunction will impose social costs that outweigh the benefits of protecting a patentee’s exclusive right to its invention; if the infringer prevails, the patentee is entitled to an ongoing royalty through the life of the patent.53 This rule adequately protects patent holders’ investment in their patent and avoids the uncertainty created by eBay.