Now that the early burst of executive orders has been completed, many political observers are turning their attentions to another pressing policy matter: What tariffs will President Trump decide to impose? As far as I can see, this question is wide open, encompassing the sub-questions of a) upon whom the tariffs will be placed; b) how big those tariffs will be; and c) for what purpose they will be sought. In return, I have a question of my own: At what point, exactly, did this become the preserve of the presidency?

I understand that, unlike with taxation, the legal history here is unclear. But why is it unclear? Why did anyone — the president, the Congress, the courts — come to think that all tax policy had to go through Congress but that some tariff policy did not? The most frequently cited Supreme Court decision in this area is J. W. Hampton, Jr. & Company v. United States. That held that Congress could delegate the power to set tariffs to the president providing that the grant was within “defined limits” and contained an “intelligible principle.” But this is ridiculous, no? Clearly, we would not allow Congress to pass a law that permitted the president to set the tax rates based on what he thought was necessary — even if he considered doing so to be in the interests of establishing a salutary foreign policy or of dealing with an “emergency.” So why tariffs?

The answer cannot be textual, given that the taxation and tariff powers sit within the same provision in the Constitution. Article I, Section 8, Clause 1 reads:

The Congress shall have Power To lay and collect Taxes, Duties, Imposts and Excises, to pay the Debts and provide for the common Defence and general Welfare of the United States; but all Duties, Imposts and Excises shall be uniform throughout the United States;

Nor did the Sixteenth Amendment include any verbiage that distinguishes it from the original text. On the contrary, the Sixteenth Amendment begins identically to Article I, Section 8, Clause 1, holding that “The Congress shall have power to lay and collect taxes on incomes, from whatever source derived, without apportionment among the several States, and without regard to any census or enumeration.” Why, then, do we insist upon Congress in one case, and in the other allow the president free rein? Article II, which establishes the powers of the presidency, makes no mention of either tariffs or taxes, which means that any powers that the executive enjoys must by definition come from the legislature. Why have we split up that legislative power and indulged delegation for only half of it?

It is undoubtedly true that, as a political matter, the area of tariffs gets less attention than the area of taxes because tariffs represent such a small piece of federal revenues. But that wasn’t always the case. Indeed, for the first half of American history, tariffs accounted for pretty much all the money the Treasury collected. Despite this, tariff rates were invariably set by Congress, not by the president. Indeed, it was only in the mid-1930s — after the income tax had become the main source of cash — that legislators began to invite the president to fill in the blanks. Per the Congressional Research Service, the Tariff Act of 1930 “was the last tariff act in which Congress set rates.” After that — under Franklin Roosevelt — that power was “delegated.” I see no evidence whatsoever to suggest that this development was constitutional, and a great deal of evidence to suggest that it was not. The text seems clear, the history seems clear, and the systemic logic seems clear, too: Changes to the laws of the United States are made by Congress, not by the president. That tariffs have been allowed to escape the confines seems like an ugly accident of history — and one that ought to be remedied fast.