The U.S Supreme Court case Southwestern Oil Company v. State of Texas in 1909 revolved around the issue of taxation and interstate commerce. The Southwestern Oil Company, a Louisiana corporation, was sued by the state of Texas for unpaid taxes on gasoline stored in its tanks within the state but destined for sale outside it. The company argued that this tax violated their rights under the Commerce Clause as they were engaged in interstate commerce since all oil products held were intended to be sold out-of-state. However, the court ruled against them stating that until goods have actually started moving from one state to another or are committed to control of a carrier for transportation purposes, they remain part of general mass within their originating location and hence can be subjected to local regulation and taxation without violating any constitutional provision regarding interstate commerce. Thus, even though these goods were intended for out-of-state sales, because they remained physically present within Texas at time when tax was assessed; such imposition did not interfere with federal power over interstate trade.

In the dissenting opinion for Southwestern Oil Company v. State of Texas, it was argued that the state's imposition of a tax on oil and gas companies based on their gross receipts violated both due process and equal protection clauses under the Fourteenth Amendment. The justice contended that this form of taxation unfairly targeted these specific industries while exempting others from similar obligations, creating an unjustifiable inequality among businesses within Texas. Furthermore, they believed that taxing gross receipts rather than net income or property value could potentially lead to situations where companies were taxed more heavily than their actual worth or earnings justified - a clear violation of due process rights as per his interpretation. They also raised concerns about potential double taxation if other states followed suit with similar laws.