Keeping the Bar High

Although the Supreme Court rejected the Federal Circuit’s “absolute bar” to the doctrine of equivalents, the new presumption of prosecution history estoppel, after Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., Ltd., sets the standard nearly as high. Indeed, a patentee may rebut this presumption only through evidence that (a) the equivalent was unforeseeable; (b) the rationale underlying the amendment bears only a tangential relation to the equivalent; or (c) there was some other reason why the patentee could not reasonably be expected to have described the equivalent. This article examines questions regarding the application of these rebuttable presumption factors, including those concerning the relative weight of each factor, the time at which amendments must be foreseeable, and the counterintuitive incentive that the foreseeability factor appears to create. Finally, this article presents strategies for avoiding the Festo dilemma altogether.