In the case of Hart Refineries v. Harmon, Treasurer of the State of Montana in 1928, Hart Refineries challenged a tax imposed by the state on oil produced within its borders. The company argued that this tax violated both their rights under the Fourteenth Amendment and also conflicted with federal law governing interstate commerce. However, the Supreme Court upheld Montana's right to impose such a tax. The court found that while states cannot interfere with interstate commerce directly or discriminate against it unfairly, they can levy taxes on businesses operating within their jurisdiction as long as those taxes are applied equally to all similar businesses and do not create an undue burden on out-of-state companies specifically.

In the dissenting opinion for Hart Refineries v. Harmon, it was argued that the majority's decision to uphold Montana's tax on petroleum products violated both due process and equal protection clauses of the Fourteenth Amendment. The dissent contended that this tax unfairly targeted out-of-state companies while exempting local businesses from similar taxation. They believed this created an unjust burden on interstate commerce, which is constitutionally protected against discriminatory state legislation. Furthermore, they disagreed with the majority’s interpretation of “original package” doctrine in relation to oil transported into Montana by pipelines; arguing instead that such oil should be considered as being in its original package until sold or used within the state and thus not subject to taxation upon entry into Montana under existing precedents set by previous Supreme Court rulings.