The commerce clause, by its own force, prohibits discrimination against interstate commerce, whatever its form or method, and the decisions of the court have recognized that there is scope for its like operation when state legislation nominally of local concern is in point of fact aimed at interstate commerce, or by its necessary operation is a means of gaining a local benefit by throwing the attendant burdens on those without the state. The commerce clause has also been thought to set its own limitation upon state control of interstate rail carriers so as to preclude the subordination of the efficiency and convenience of interstate traffic to local service requirements.
Truckers and others, filed suit against the state highway department and others, alleging that 1933 S.C. Acts 259 (Act) was an unconstitutional burden on interstate commerce and infringed due process. The provisions of the Act that were at issue provided that trucks whose gross weight, including load, exceeded 20,000 pounds, and trucks whose total outside width exceeded 90 inches could not be operated on the state highways.
Despite the possible burden on interstate commerce, can the state enact legislation to regulate semi-trailor motor trucks on its highways?
The court found that while the constitutional grant to congress of power to regulate interstate commerce allowed it to curtail state power, it did not forestall all state action affecting interstate commerce. As long as the state action did not discriminate against interstate commerce, the burden on interstate commerce was one which the constitution permitted because it was an inseparable incident of the exercise of a legislative authority, which, under the constitution, had been left to the states. The court found that there was adequate support for the legislative judgement that led to the enactment of the Act and the measures taken by the state were within its legislative power.