The United States Supreme Court case, United States v. American Freightways Co., 1956, revolved around the interpretation of a federal statute that regulated the rates charged by motor carriers. The government argued that American Freightways had overcharged for its services and sought reparations under Section 16(3)(a) of the Interstate Commerce Act. However, American Freightways contended that it was not liable because it had filed tariffs with the Interstate Commerce Commission (ICC), as required by law, which were in effect at the time of shipment. The key issue before the court was whether or not a carrier could be held liable for reparations if they followed their filed tariff rate but later found to have violated ICC regulations due to being unreasonable or discriminatory. In this case, Justice Frankfurter delivered an opinion affirming lower courts' rulings favoring American Freightways. He stated that while carriers are obligated to charge reasonable rates and avoid discrimination among shippers under ICC rules; however, when they follow their legally-filed tariffs - even if those tariffs are later deemed unreasonable - they cannot be held responsible for reparation claims based on alleged overcharges.

In the dissenting opinion for United States v. American Freightways Co., it was argued that the majority's decision to uphold a ruling by the Interstate Commerce Commission (ICC) regarding freight rates was incorrect. The dissenting justices believed that there were significant procedural errors in how the ICC reached its conclusion, including an alleged failure to properly consider all relevant evidence and arguments presented by American Freightways. They also took issue with what they saw as an overly broad interpretation of federal law governing interstate commerce, arguing that this could potentially lead to unjust outcomes in future cases. Furthermore, they expressed concern about potential negative impacts on competition within the trucking industry if such rulings were allowed to stand unchallenged.