In the 1993 case Associated Industries of Missouri, et al. v. Janette M. Lohman, Director of Revenue of Missouri, et al., the United States Supreme Court ruled on a tax dispute between businesses and the state government in Missouri. The issue at hand was whether or not it was constitutional for Missouri to tax out-of-state companies at a higher rate than in-state companies for their use of fuel within state borders. The plaintiffs argued that this practice violated both the Commerce Clause and Equal Protection Clause by discriminating against interstate commerce and treating similar entities differently without sufficient justification respectively. The court held that there was no violation as long as there is some rational basis for such differential treatment under Equal Protection analysis; here, promoting local business could be seen as one such reason even though it may disadvantage out-of-state competitors somewhat. As per Commerce clause challenge too, they found no discrimination because all carriers were taxed equally on fuel purchased within State irrespective of where it's consumed while only those who bought elsewhere but used inside had to pay additional compensating tax which seemed fair enough considering benefits they derived from using State’s highways.

In the dissenting opinion for Associated Industries of Missouri v. Lohman, Justice Blackmun argued that the majority's decision to uphold Missouri's tax scheme was flawed because it violated the Commerce Clause by discriminating against interstate commerce. He contended that this tax system imposed a heavier burden on out-of-state businesses than in-state ones, thereby creating an unfair advantage for local companies and discouraging economic competition across state lines. Furthermore, he disagreed with the majority’s view that there was no practical alternative to this taxing method; instead suggesting other non-discriminatory alternatives could be implemented without causing undue hardship or complexity. Thus, he believed that upholding such a discriminatory taxation policy set a dangerous precedent and undermined principles of fair trade and competition inherent in our federal system.