In the 1904 case of Adams Express Company v. Iowa, the U.S. Supreme Court ruled in favor of Adams Express Company, a private express company that transported goods across state lines. The State of Iowa had imposed a tax on the gross receipts earned by the company within its borders, which included earnings from interstate commerce activities. The court held that this taxation was unconstitutional as it violated both due process and equal protection clauses under Fourteenth Amendment and also infringed upon Congress's exclusive power to regulate interstate commerce under Commerce Clause (Article I, Section 8) of Constitution. This decision reinforced federal supremacy over states in matters related to interstate commerce regulation.

In the dissenting opinion for Adams Express Company v. Iowa, 1904, it was argued that the state of Iowa had overstepped its jurisdiction by imposing a tax on an interstate commerce company. The dissenting justices believed that this case fell under federal authority due to the nature of interstate commerce and thus should not be subject to state taxation laws. They contended that allowing states to impose taxes on such companies could potentially disrupt or impede national trade and economic growth as each state could set their own rates, leading to inconsistencies across borders. Furthermore, they expressed concern about potential double taxation if multiple states claimed taxing rights over one entity's operations in different locations within those states.