The U.S. Supreme Court case National Private Truck Council, Inc., et al. v. Oklahoma Tax Commission et al., 1994 dealt with the issue of whether an Oklahoma tax on motor carriers was discriminatory and thus violated the Commerce Clause of the Constitution. The state imposed a flat fee on all trucks registered in Oklahoma, but also levied a higher fee for out-of-state vehicles operating within its borders based on mileage driven in the state during previous years. The National Private Truck Council (NPTC) argued that this system unfairly burdened interstate commerce by imposing greater costs on out-of-state trucking companies than those based in Oklahoma. In their decision, the Supreme Court sided with NPTC and ruled that such differential treatment did indeed violate the Commerce Clause as it discriminated against interstate commerce by favoring local businesses over their out-of-state competitors without offering any corresponding benefits or services to justify these additional charges.

In the dissenting opinion for the National Private Truck Council, Inc., et al. v. Oklahoma Tax Commission et al., Justice Stevens argued that Oklahoma's tax scheme did not violate the Commerce Clause of the U.S Constitution as it treated in-state and out-of-state businesses equally. He disagreed with majority’s interpretation of Complete Auto Transit, Inc. v Brady case which was used to evaluate constitutionality under commerce clause and stated that this case does not require benefits received by taxpayer to be precisely related or proportional to taxes paid; rather a rough approximation is sufficient enough if it is fairly related. He also pointed out that there were no findings indicating any significant difference between services provided by state to local vs interstate trucks hence he believed such tax should be upheld unless proven discriminatory or excessive beyond fair share contribution towards cost of services provided by state.