The U.S. Supreme Court case Westinghouse Electric and Manufacturing Company v. Wagner Electric and Manufacturing Company in 1911 revolved around a patent dispute between the two companies over an invention related to electric circuit breakers, specifically automatic cut-outs for dynamo-electric machines. The court ruled in favor of Westinghouse, holding that their patent was valid and had been infringed upon by Wagner. The decision hinged on the interpretation of what constituted "invention" under patent law; while both parties' devices performed similar functions, it was determined that Westinghouse's design involved more than just mechanical skill or knowledge but also inventive genius which deserved protection under the law.

In the dissenting opinion for Westinghouse Electric and Manufacturing Company v. Wagner Electric and Manufacturing Company, it was argued that the patent in question should not have been invalidated. The justice disagreed with the majority's interpretation of prior art, arguing that previous designs did not anticipate or make obvious the patented invention. They contended that earlier patents lacked crucial elements present in Wagner’s design which made a significant difference to its operation and efficiency. Furthermore, they believed there were factual errors in how lower courts had interpreted evidence related to these differences. Therefore, they felt this case warranted further examination rather than outright dismissal on grounds of invalidity due to anticipation by prior art.