The U.S. Supreme Court case Selliger v. Commonwealth of Kentucky, by Alexander, Revenue Agent in 1908 revolved around the issue of taxation and interstate commerce. The plaintiff, a resident of Indiana who sold liquor to customers in Kentucky via mail order or delivery services without having a physical presence or license in Kentucky was sued for tax evasion by the state's revenue agent. The plaintiff argued that his business operations were protected under the Interstate Commerce Act which prohibits states from taxing businesses operating across state lines unless they have a physical presence within their borders. However, the court ruled against him stating that while it is true that states cannot impose taxes on interstate commerce as per federal law; this does not exempt individuals from paying taxes on goods sold within those states even if they are conducting business remotely from another location outside its jurisdictional boundaries. Therefore, despite being based out-of-state he was still liable to pay sales tax for all transactions made with customers residing inside Kentucky since these constituted local rather than interstate trade activities according to existing laws at that time.

In the dissenting opinion for Sellinger v. Commonwealth of Kentucky, Justice Harlan argued that the majority's decision was inconsistent with previous rulings and violated constitutional principles. He contended that a state cannot impose taxes on goods imported from other states or foreign countries while they remain in their original packages and have not yet been mixed with general property of the state. The justice believed this principle to be fundamental to free trade among states, which is protected by the Constitution. In his view, allowing such taxation would lead to protectionism at a state level, undermining national unity and economic integration. Furthermore, he disagreed with the majority's interpretation of 'original package', arguing it should include any form in which goods are delivered by an importer for sale.