The United States Supreme Court case of United States v. Union Supply Company in 1909 revolved around the issue of whether or not a company could be held liable for damages caused by its employees while they were performing their duties. The Union Supply Company was sued by the U.S government after one of its employees, who was operating a steam shovel on behalf of the company, damaged some property owned by the federal government. The court ruled that an employer is indeed responsible for any damage caused by an employee during his employment under certain conditions - specifically when such actions are within the scope and nature of his job responsibilities and done with intent to benefit or further interests of his employer. This ruling established important legal precedent regarding vicarious liability in American law.

In the dissenting opinion for United States v. Union Supply Company, it was argued that the majority's decision to uphold a tax on coal mined from tribal lands violated established principles of federal Indian law and policy. The dissenters contended that the imposition of such a tax constituted an infringement upon tribal sovereignty and self-determination, as well as an unjustified intrusion into tribal economic affairs. They also pointed out that this taxation could potentially discourage future development in these areas by making mining operations less profitable. Furthermore, they disagreed with the majority's interpretation of relevant statutes and treaties, arguing instead that these legal instruments were intended to protect tribes from exactly this kind of governmental interference. Finally, they expressed concern about potential negative impacts on tribes' ability to negotiate beneficial agreements with private companies if those companies had to factor in additional costs imposed by federal taxes.