In the 1944 case Interstate Commerce Commission et al. v. Parker, doing business as Parker Motor Freight, et al., the U.S Supreme Court dealt with a dispute over interstate commerce regulations and their application to motor carriers. The Interstate Commerce Commission (ICC) had issued an order requiring all motor carriers involved in interstate trade to file reports detailing their financial operations and other relevant data for regulatory purposes. However, Mr. Parker challenged this order on grounds that it exceeded ICC's statutory authority under Part II of the Motor Carrier Act of 1935 because he was not engaged in "for-hire" transportation but rather private carriage exempt from such regulation by ICC. The Supreme Court ruled against Mr.Parker stating that even though his operation was classified as private carriage due to its contractual nature with specific clients only, it still constituted part of interstate commerce which falls within ICC's jurisdiction according to Section 203(a)(14) & (17). Therefore, they were required to comply with reporting requirements set forth by ICC for effective control and supervision over national transportation system ensuring fair competition among different modes of transport.

The dissenting opinion in the case of Interstate Commerce Commission et al. v. Parker, Doing Business as Parker Motor Freight, et al., argued that the majority's decision to uphold a ruling by the Interstate Commerce Commission (ICC) was incorrect and overstepped its authority under federal law. The ICC had ruled that it could regulate contract carriers like Parker Motor Freight as if they were common carriers, despite statutory language suggesting otherwise. The dissent contended this interpretation was an unwarranted expansion of regulatory power not supported by Congress' intent when drafting relevant legislation. They believed that contract carriers should be treated differently from common carriers due to their distinct business models and contractual obligations with specific customers rather than serving the general public indiscriminately.