In the United States v. Adams et al., 1965, the Supreme Court ruled in favor of William P. Adams and his co-defendants who were charged with violating a federal statute that prohibited unauthorized possession of U.S. Treasury checks. The defendants had found discarded mailbags containing undelivered government checks and cashed them instead of returning them to postal authorities or their intended recipients. The court held that since the law required knowledge that possession was unlawful, it did not apply to those who innocently came into possession of such items without knowing they were doing something illegal - as was argued by Adams' defense team. The case is significant because it clarified how "knowingly" should be interpreted within criminal statutes; specifically, whether this term refers only to awareness of one's actions or also includes an understanding that these actions are illegal under federal law.

In the dissenting opinion for United States v. Adams et al., Justice Black argued that the majority's decision to invalidate a patent held by the U.S. government was incorrect and set a dangerous precedent. He contended that, under existing law, an invention must be "obvious" in order to be ineligible for patent protection; however, he believed this standard had not been met in this case as there were no prior patents or publications describing such an invention. Furthermore, he noted that expert testimony during trial suggested it would not have been obvious to someone skilled in battery technology at the time of its creation. Therefore, according to Justice Black’s interpretation of patent laws and his assessment of evidence presented during trial proceedings, he disagreed with majority’s ruling which invalidated Adam's wet-battery patent on grounds of 'obviousness'.