Several nineteenth century Supreme Court cases applied this clause to duties and imposts on interstate imports and exports.
[3] The national government lacked power to enforce acts of Congress and requests for money from the states were frequently ignored.
[8] In Clyde Mallory Lines v. Alabama, the Supreme Court explained that the prohibition on tonnage duties "was due to the desire of the framers to supplement [the Import-Export Clause] ... by forbidding a corresponding tax on the privilege of access by vessels to the ports of a state, and to their doubts whether the Commerce Clause would accomplish that purpose.
In addition to the four-prong test in Complete Auto Transit, the court added two prongs derived from the Import-Export Clause: whether the tax creates a risk of multiple taxation and whether it impairs the federal government's one voice in dealing with foreign nations.
[5]: 528 In West Lynn Creamery, Inc. v. Healy, for example, the Supreme Court cited a tariff as "the paradigmatic example of a law discriminating against interstate commerce ... so patently unconstitutional that our cases reveal not a single attempt by any State to enact one.
The plaintiff in the case was charged, and found guilty by the Maryland courts, with selling one package of foreign dry goods without a license.
The court's opinion, written by Chief Justice John Marshall,[17] began with a lexicographical analysis of the clause:[17]: 436–437 An impost, or duty on imports is a custom or a tax levied on articles brought into a country, and is most usually secured before the importer is allowed to exercise his rights of ownership over them, because evasions of the law can be prevented more certainly by executing it while the articles are in its custody.
"[17]: 445 The opinion concluded by noting two issues that were left open: "It may be proper to add that we suppose the principles laid down in this case to apply equally to importations from a sister state.
[18] "We think this case cannot be distinguished from that of Brown v. Maryland,"[18]: 173 he wrote, concluding that "the state tax in question is a duty upon the export of gold and silver, and consequently repugnant to the [Import-Export Clause].
The court began by examining the usage of the terms "imports" and "imposts" in Brown: In the case of Brown v. Maryland, the word imports, as used in the [Import-Export Clause], is defined, both on the authority of the lexicons and of usage, to be articles brought into the country; and impost is there said to be a duty, custom, or tax levied on articles brought into the country.
In the ordinary use of these terms at this day, no one would, for a moment, think of them as having relation to any other articles than those brought from a country foreign to the United States, and at the time the case of Brown v. Maryland was decided.
[1]: 133–136 The court's final line of reasoning was that application of the Import-Export Clause to interstate commerce would produce "the grossest injustice"[1]: 137 and that the "equality of public burdens in all our large cities [would be] impossible,"[1]: 137 because contemporary case law prohibited the taxation of imports.
"[1]: 137 Justice Samuel Nelson dissented from the court's ruling in Woodruff, reasoning first that the majority's decision leaves "no security or protection ... in this government against obstructions and interruptions of commerce among the States,"[19]: 141 which was one of the primary issues prompting the Constitutional Convention.
[20] Justice Nelson further critiqued the court's lexicographical inquiry: In looking at this clause, it will be seen that there is nothing in its terms, or connection, that affords the slightest indication that it was intended to be confined to the prohibition of a tax upon foreign imports.
Surely, if this had been intended, it must have occurred to the distinguished members of the Convention, it would be quite important to say so that the prohibition might not be misunderstood, especially when we take into consideration the eminent men who not only discussed and settled the terms and meaning of the clause, but to whom the whole instrument was committed for special and final revision.
[19]: 143–147 In 1945, the Supreme Court held that the Import-Export Clause applied to imports from the Philippine Islands, which at that time was a territory of the United States.
The case concerned whether a local ad valorum tax on a business' inventory could be applied to imported tires held in a Michelin warehouse pending distribution to the company's retail outlets.
Under the "original package" doctrine, the tires could not be subjected to even non-discriminatory taxes until they lost their character as imports and became incorporated into the general mass of property of the state.
[5]: 530 The question before the U.S. Supreme Court was whether the tires had lost their "distinctive character" as imports once they were unloaded from the sea-vans, sorted, and stored in Michelin's warehouse.