In the United States Supreme Court case of The United States v. One Case of Clocks, Lion, Pinsard and Co., Claimants, the court was asked to decide whether a duty imposed on imported clocks by Congress in 1842 could be collected from an importer who had purchased them prior to that date. The claimants argued that they should not have to pay this duty because it would constitute an ex post facto law which is prohibited by Article I Section 10 of the Constitution. However, the court ruled against them stating that since there was no evidence showing when exactly these clocks were imported into the country or how long they had been stored before being sold at auction in 1843, it could not be determined if their importation predated or postdated Congress’s imposition of duties on foreign goods. Therefore, as per established precedent regarding taxation laws passed after goods are brought into a country but before they are consumed domestically for commercial purposes; Lion et al must pay any applicable taxes due upon their sale regardless of when those taxes were enacted.

In the case of The United States, Plaintiffs in Error v. One Case of Clocks, Lion, Pinsard and Co., Claimants, the dissenting opinion was that Congress had not intended to grant a right to seize goods imported from France without payment of duties due on them under existing laws. The majority opinion held that such seizures were authorized by law as an exercise of power granted to Congress by the Constitution; however Justice McLean argued that this interpretation would lead to unjust results and be contrary to public policy. He noted that it could result in arbitrary seizures which would violate principles established by prior decisions regarding property rights and due process protections for individuals accused or suspected of violating customs regulations. Furthermore he argued there was no evidence indicating Congress had ever intended such broad authority over imports when they passed legislation related thereto.