In the United States v. Passavant case of 1897, the Supreme Court ruled on a matter concerning customs duties. The defendant, Passavant, had imported iron bands from Germany and declared them as hoop iron to U.S. Customs officials in order to pay lower import duties than those applied for steel strips or bands which were more expensive under tariff laws at that time. However, upon inspection by customs officers it was determined that these items were not hoop iron but rather steel strips or bands and thus subject to higher duty rates. The court held that despite any potential confusion over terminology used in different countries (i.e., what might be considered "hoop iron" in Germany could be classified differently in America), it is ultimately up to the importer to accurately declare their goods according to American classifications when importing into the U.S.. Therefore, they upheld charges against Passavant for attempting evasion of proper custom duties.

In the dissenting opinion for United States v. Passavant, it was argued that the government did not have sufficient evidence to prove that Passavant had knowingly and willingly conspired to defraud the United States. The dissenting justices believed that while there may have been some questionable actions on Passavant's part, these alone were not enough to establish a clear intent of conspiracy or fraud. They also questioned whether certain pieces of evidence should have been admitted in court, as they felt this information could potentially bias the jury against Passavant without directly proving his guilt. Furthermore, they disagreed with how instructions were given to the jury regarding what constituted conspiracy and fraud under law; arguing these definitions were too broad and vague which could lead jurors into making an incorrect decision based on misunderstanding or misinterpretation of legal terms.