Kewanee Oil Co. v. Bicron Corp., 416 U.S. 470, 94 S. Ct. 1879, 40 L. Ed. 2d 315 (1974) (Supreme Court of the United States)
Kewanee Oil Co. v.
Does federal patent law preempt state trade secret law that protects against the unauthorized use or disclosure of unpatented, potentially patentable information obtained through breaches of confidence or other improper means?
Federal patent law does not preempt state trade secret law so long as the state law (1) protects only secret information against improper acquisition, use, or disclosure (e.g., through breach of confidence or other wrongful conduct), (2) permits reverse engineering and independent discovery, and (3) does not prohibit copying or use of information that is publicly available or in the public domain. In this posture, state trade secret protection does not conflict with the objectives of the patent system and is therefore not preempted.
No. State trade secret law, as exemplified by Ohio's common law of trade secrets, is not preempted by federal patent law. Because trade secret law protects only secret information from misappropriation and allows reverse engineering and independent discovery, it does not frustrate the federal patent system's goal of encouraging disclosure of inventions and does not confer patent-like protection over publicly available ideas.
Kewanee is the cornerstone of modern trade secret preemption doctrine. It establishes that state trade secret regimes—when limited to preventing misappropriation of confidential information and permitting reverse engineering and independent discovery—operate in harmony with the federal patent system. The decision reassures innovators that they may choose between patenting and secrecy without rendering state remedies constitutionally suspect, and it cabins the broader preemption language of Sears and Compco to situations where states confer patent-like exclusivity over publicly available subject matter. Kewanee informs later decisions, including Bonito Boats, which invalidated a state law barring reverse engineering precisely because it conflicted with the principles Kewanee approved. For law students, the case provides the analytical framework for evaluating preemption across IP regimes: identify the federal objective, assess whether the state law removes material from the public domain or bars legitimate copying, and determine whether the state interest (e.g., commercial ethics and investment in R&D) complements federal policy.