In the United States v. Bayer et al., 1946, the Supreme Court ruled in favor of the government regarding a patent dispute with pharmaceutical company Bayer. The case revolved around whether or not Bayer's patent for aspirin was valid and enforceable under U.S. law. The court held that since "aspirin" had become a generic term in public usage before Bayer obtained its trademark registration, it could not be exclusively owned by any one entity as per U.S laws on trademarks and patents. The ruling set an important precedent about how common use of a name can affect intellectual property rights - if a product becomes so widely known by its brand name that it is used generically to refer to an entire category of products, then this may invalidate exclusive ownership claims over that name.

The dissenting opinion in the United States v. Bayer et al., 1946 case argued that the majority's decision to uphold a conviction based on evidence obtained through wiretapping was incorrect. The dissenters believed this violated the Fourth Amendment, which protects against unreasonable searches and seizures. They contended that allowing such practices would set a dangerous precedent for future cases, potentially undermining citizens' constitutional rights. Furthermore, they disagreed with the majority's assertion that wiretapped conversations were admissible as long as they were relevant to the case at hand; instead, they maintained these should be excluded due to their invasive nature and potential for misuse by law enforcement agencies.