The U.S. Supreme Court case Minneapolis, St. Paul & Sault Ste. Marie Railway Company v. C.L. Merrick Company in 1920 revolved around a dispute over freight charges for the transportation of goods by rail between the two parties involved - the railway company and C.L Merrick Company, a grain dealer firm based in Minnesota that shipped its products across state lines using the services of several railroad companies including defendant's line. The main issue was whether or not certain provisions of an act to regulate commerce were applicable to this situation and if they allowed recovery from carriers who charged more than their filed tariff rates for interstate shipments under special contracts with shippers like plaintiff. In its decision, The Supreme Court held that such contracts violated federal law which required all railroads to charge only those rates they had officially filed with Interstate Commerce Commission (ICC). It further ruled that any shipper paying higher than these established tariffs could recover excess payments even if it had agreed upon them through private contract as it contravened public policy aimed at preventing discrimination among shippers.

In the dissenting opinion for the case of Minneapolis, St. Paul & Sault Ste. Marie Railway Company v. C.L. Merrick Company, Justice McReynolds argued that the majority's decision was a departure from established principles and precedent regarding interstate commerce law and railway transportation regulations. He contended that under existing laws, railroads were permitted to set their own rates unless they were deemed unreasonable by regulatory bodies such as the Interstate Commerce Commission (ICC). In this case, he believed there was no evidence suggesting that the rate charged by the railroad company was unjust or discriminatory in any way; thus it should not have been subject to judicial review or alteration without clear proof of its unreasonableness or discrimination against shippers like Merrick Company.