The U.S. Supreme Court case Eastern-Central Motor Carriers Association et al. v. United States et al., 1943, revolved around the Interstate Commerce Commission's (ICC) decision to allow an increase in freight rates by rail carriers without a corresponding increase for motor carriers. The Eastern-Central Motor Carriers Association and other trucking companies challenged this decision, arguing that it was discriminatory and violated the Interstate Commerce Act which required equal treatment of all types of transportation services under similar conditions. However, the Supreme Court upheld ICC’s decision stating that different modes of transport could be treated differently if there were substantial reasons for doing so - such as differences in cost structures or market conditions between rail and road transportations. The court ruled that ICC had not acted arbitrarily or capriciously when it allowed only railroad companies to raise their prices due to wartime inflation while denying a similar request from trucking firms because they did not face equivalent financial pressures.

In the dissenting opinion for Eastern-Central Motor Carriers Association et al. v. United States et al., Justice Frankfurter disagreed with the majority's interpretation of Section 216(g) of the Motor Carrier Act, arguing that it was not intended to allow motor carriers to change their rates without first obtaining approval from the Interstate Commerce Commission (ICC). He believed that such a reading would undermine ICC’s regulatory authority and disrupt established practices in rate-making procedures. Furthermore, he argued that this decision could lead to potential abuses by allowing carriers to unilaterally impose new rates before they have been deemed just and reasonable by ICC. In his view, Congress had intended for any changes in rates under Section 216(g) to be subject to prior approval by ICC as a safeguard against unjust or unreasonable charges.