The Supreme Court Case that the Federal Circuit Overruled: Westinghouse v. Boyden Power Brake Co.

28 Pages Posted: 8 Mar 2018 Last revised: 3 Apr 2018

Samuel Ernst

Golden Gate University School of Law

Date Written: March 28, 2018


Can a federal court of appeals overrule Supreme Court precedent? Not overtly. But if nobody takes notice, a circuit court can undermine Supreme Court precedent, vacating lower court decisions that rely on the precedent and announcing in published opinions that a once robust doctrine has somehow suddenly become archaic, disfavored, and rarely applied. This is how the Court of Appeals for the Federal Circuit has caused an important Supreme Court patent law doctrine to vanish: The reverse doctrine of equivalents, as first announced by the Court in the 1898 case Westinghouse v. Boyden Power Brake Co. Hence Westinghouse represents forgotten precedent in a different sense than is conventionally thought: The leading patent court in the nation has requested that we forget this precedent, with the result that the case is receding from memory and relevance, unless and until the Supreme Court intervenes.

In Westinghouse, the Supreme Court established that two steps are necessary to determine if an accused product infringes a patent. Yes, it is first necessary to analyze whether an accused product falls within the literal language of the patent claims. But even if it does, infringement is not proven if the accused infringer has so far changed the principle of the patented invention as to create a new, substantially superior innovation that solves the problem in the prior art in a way the patented invention failed to do. The Court in Westinghouse ruled that just as “a charge of infringement is sometimes made out, though the letter of the claims be avoided . . . [t]he converse is equally true.” In other words, just as there is an affirmative doctrine of equivalents to allow patent holders to establish that an infringer really has appropriated a patented invention despite avoiding the literal scope of the claims, so too there is a reverse doctrine of equivalents to allow accused infringers to establish that the patented invention has not been appropriated despite the fact that the claim language semantically reads on the accused device. In 1950 the Supreme Court referred to the “wholesale realism” of this doctrine, because it prevents patent infringement from being reduced to a mechanical, linguistic exercise that fails to probe the substance of the patent infringement question.

For nearly one hundred years following Westinghouse, the reverse doctrine of equivalents was a necessary safety valve in patent law to ensure that granting the patent monopoly did not impede the “progress” sought by the Intellectual Property Clause of the Constitution. In cases where the accused product represents a leap forward in the technology far beyond what is disclosed in the asserted patent, society benefits from access to that superior innovation unimpeded and untaxed by the asserted patent. There are over thirty published opinions finding or affirming noninfringement under the reverse doctrine of equivalents between 1898 and the 1982 creation of the Federal Circuit and uncounted additional unpublished dispositions as well as opinions denying or vacating summary judgment of infringement due to a dispute of fact regarding reverse equivalency. In at least the Second, Fifth, Sixth, Seventh, and Ninth Circuits, and indeed as stated by the Supreme Court itself in Westinghouse, reverse equivalency always had to be considered as part of the principal infringement case.

The reverse doctrine of equivalents enjoyed steady application by the courts in the decades since the 1898 Westinghouse case until the 1980s, when the Federal Circuit was created and proceeded to stamp out the doctrine. In the 1980s the Federal Circuit regularly vacated or reversed findings of noninfringement under the reverse doctrine of equivalents to the point where such findings of noninfringement have disappeared altogether. In 2002 the Federal Circuit proclaimed final victory over the reverse doctrine of equivalents, mischaracterizing it as an “anachronistic exception, long mentioned but rarely applied . . . .” Subsequently, the Federal Circuit warned the lower courts that “this court has never affirmed a finding of noninfringement under the reverse doctrine of equivalents.” And it likely never will, unless an intrepid petitioner for certiorari someday convinces the Supreme Court to revive the doctrine.

Keywords: Patent Law, Supreme Court, Federal Circuit, Reverse Doctrine of Equivalents

Suggested Citation

Ernst, Samuel, The Supreme Court Case that the Federal Circuit Overruled: Westinghouse v. Boyden Power Brake Co. (March 28, 2018). Syracuse Law Review, Vol. 68, No. 53, 2018. Available at SSRN:

Samuel Ernst (Contact Author)

Golden Gate University School of Law ( email )

536 Mission Street
San Francisco, CA 94105
United States


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