In the case of United States v. Hark et al., co-partners, doing business as Liberty Beef Co., the Supreme Court ruled on an issue related to price control during World War II. The defendants were charged with selling meat at prices above those set by the Emergency Price Control Act of 1942, which was enacted to prevent inflation during wartime. They argued that they should not be held liable because they had relied in good faith on a directive from a government official who misinterpreted the law's pricing regulations. However, their argument was rejected by both lower courts and eventually by the Supreme Court too. The court held that ignorance or misunderstanding of law is no defense against liability for violation even if it resulted from misleading advice given by a government officer tasked with administering or enforcing it.

In the dissenting opinion for United States v. Hark et al., Justice Frank Murphy argued that the majority's decision was a misinterpretation of the Emergency Price Control Act and its intent. He believed that Congress intended to protect consumers from price gouging during times of crisis, not to punish small businesses who may have inadvertently violated complex regulations. In his view, criminal penalties should only apply in cases where there is clear evidence of willful violation or profiteering behavior. By applying these penalties broadly, he feared it would discourage honest businessmen from participating in vital industries during wartime out of fear they might unintentionally violate some obscure provision and face severe punishment as a result.