The Volokh Conspiracy
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The Tariffs Imposed by President Trump Are Unconstitutional
Presidential power must stem from the Constitution or a statute, and the tariffs imposed by President Trump are unauthorized by statute, making them both unlawful and unconstitutional.
President Trump has raised or lowered tariffs/taxes, or he has threatened other nations that he will do so, on an almost daily basis since Inauguration Day. He does not have the legal authority to do so.
The U.S. Constitution authorizes the imposition of tariffs in the very first clause of Article I, Section 8, which famously grants Congress eighteen, and only eighteen, limited and enumerated legislative powers. That Clause provides that:
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.
This provision stems from centuries of conflict in Great Britain (and the colonies) about the location of the power to tax, and from the American Revolutions rejection of Parliament's effort to impose "taxation without representation" on the colonies.
Samuel Johnson's 1755 Dictionary of the English Language defines a Duty as a "Tax; impost; custom; [or] toll." It defines an Impost as "a tax; a toll; [or] a custom paid." A tariff is either a "duty" or an "impost," and the power to impose such tariffs/taxes is therefore explicitly given to Congress, not the President, by the Constitution. From the Tariff Act of 1789, passed by the First Congress, to the Tariff of Abominations passed in 1828, to the Smoot-Hawley Tariff passed in 1930, it has always been understood that the Constitution gives only Congress the power to impose, raise, or lower tariffs, which are taxes. It does not give that power to the President.
Under case law going back to the nineteenth century, Congress can delegate some measure of power to the President to adjust tariff rates, but President Trump can only impose, raise, or lower tariffs if Congress has delegated that power to him by statute. J.W. Hampton, Jr. & Co. v. United States, 276 U.S. 394 (1928). He also can only do so as long as the delegation of power by Congress is guided by "an intelligible principle." This is a wise and good feature of our Constitution, a document which should be revered and followed, not trashed.
A superb amicus brief written by former Judge, and present-day Stanford Law Professor, Michael McConnell and by attorney Joshua Claybourn demonstrates beyond the shadow of a doubt that Congress has not delegated the sweeping power to impose, raise, lower, defer, and reinstate tariffs/taxes from day to day that President Trump has purported to exercise in the last 100 days. There is simply no statute that authorizes the Trump tariffs/taxes, especially those announced in April 2025. And there is no statutory "intelligible principle" that has guided President Trump's repeated raising, lowering, delaying, and then reinstating of tariffs/taxes.
The McConnell/Claybourne amicus brief, which I signed, can be found at this link: https://papers.ssrn.com/sol3/papers.cfm?abstract_id=5237248. It was also signed by a former U.S. Attorney General, two former Senators and a former Governor, former judges, a former Yale Law School Dean, and a former White House Counsel—all of whom have sterling reputations and who include leading liberals as well as conservatives. (The signatories are former Sen. and Gov. George F. Allen, Sen. and former Ambassador to the United Nations John C. Danforth, Prof. Richard A. Epstein, former Sen. and Secretary of Defense Charles T. Hagel, Prof. and former Yale Law School Dean Harold Hongju Koh, Prof. Gerard N. Magliocca, former Attorney General and Judge Michael B Mukasey, Prof. Alan Sykes, former Judge John Daniel Tinder, former White House Counsel Peter Wallison, and former State Department Counselor and Director of the 9/11 Commission Philip Zelikow.)
The brief explains that:
In April 2025, President Trump proclaimed a sweeping tariff regime that touches nearly every imported good sold in the United States. The measures include a 10% baseline tariff on all imports and a 34% duty on Chinese goods (raising total tariffs to 65%). These levies did not arise from legislation. They were not the product of congressional debate or any statutory process. Nor were they supported by specific findings under existing trade laws. Instead, they were imposed unilaterally, by presidential proclamation, and justified under statutes like the International Emergency Economic Powers Act ("IEEPA") and sections of the Trade Act of 1974. On April 9, 2025, President Trump announced a 90-day pause on most of these tariffs, except for those on Chinese imports, which were increased to 125%. The baseline 10% tariffs on nearly every country remained in effect.
When Congress has delegated authority in trade matters, the Court has required strict limits. In J.W. Hampton, Jr. & Co. v. United States, 276 U.S. 394 (1928), the Court upheld a tariff delegation only because it was governed by an "intelligible principle" and confined to narrow bounds. That remains the constitutional baseline. Where Congress has authorized executive action in trade policy, it has done so through specific, tightly constrained statutes—typically requiring factual findings, defined procedures, and clearly delineated circumstances.
The Trade Act of 1974 and the Trade Expansion Act of 1962 exemplify this approach. They allow the Executive to address unfair trade practices or national security threats, but only within carefully prescribed limits. Even then, these statutes do not—and constitutionally cannot—authorize the President to enact a sweeping tariff regime absent new legislation.
The absence of tariff language in IEEPA stands in sharp contrast to statutes where Congress has affirmatively granted such power. When Congress intends to authorize duties, it says so. Section 301 of the Trade Act of 1974 allows the President to "impose duties or other import restrictions." 19 U.S.C. § 2411(c)(1)(B). Section 201 of that same Act empowers the President to "proclaim an increase in, or the imposition of, any duty on the imported article" or to "proclaim a tariff-rate quota." 19 U.S.C. § 2251(a)(3)(A), (B). Similarly, Section 232 of the Trade Expansion Act authorizes the adjustment of "duties" on imports, 19 U.S.C. § 1862(a), and grants authority to "adjust the imports." Id. § 1862(c). In each case, Congress spoke with clarity when it intended to delegate authority over tariffs and it encumbered the grant of authority with procedural and substantive conditions and prerequisites."
To be fair, those constraints are often pretty thin. The President has been allowed to impose tariffs that respond to "reciprocally unequal and unreasonable" tariffs elsewhere. Field v. Clark. He can adjust tariff rates to "equalize the costs of production" between the US and other countries. Hampton. But there has to be some statutory limit somewhere.
The most important defense President Trump has made of his massive tax/tariff increase is that it is justified by the "emergency" of large trade deficits, which have been around for decades, and the "emergency" of the hollowing out of the United States's manufacturing industry, which has gone on at least since the North American Free Trade Agreement (NAFTA) went into effect thirty-one years ago in 1994.
Black's Law Dictionary Online defines an "emergency" as being a:
Situation requiring immediate attention and remedial action. [I]t involves injury, loss of life, damage to the property, or catastrophic interference with the normal activities. A sudden, unexpected, or impending situation.
The decades long trade deficit, and the hollowing out of the United States's manufacturing base, are neither (1) a sudden, unforeseen event (like a nuclear attack), which would require unilateral presidential retaliation, nor (2) problems that are so urgent and so requiring of immediate attention that they would justify "emergency" action by the President alone, without Congress's input. Tariffs may or may not be good national policy, but the Constitution and the laws of this country make that a question that Congress must deal with pursuant to Article I, Section 7 and not the President alone.
IEEPA, the statute that President Trump relied on in imposing his April 2025 tariffs/taxes, was passed to limit such carte blanche power to impose tariff/taxes when it was claimed by President Richard M. Nixon. IEEPA is clearly constitutional insofar as it cut back on the power President Nixon claimed under an earlier and now defunct statute. This is because the Constitution explicitly gives the power to impose "duties" and "imposts," as it calls tariffs, to Congress acting pursuant to Article I, Section 7, and not to the President alone.
There is no ambiguity here, and no long-standing presidential practice of Presidents imposing, raising, lowering, deferring, and reinstating tariffs/taxes outside of statutory authority, as some of have claimed might be the case with respect to the impoundment of congressionally appropriated funds. United States v. Midwest Oil Co., 236 U.S. 459 (1915) (long-standing presidentially claimed power acquiesced in by Congress for decades may be constitutional); Youngstown Sheet & Tube Co. v. Sawyer, 343 U.S. 579 (1952) (Frankfurter, J. concurring) (longstanding presidential practice acquiesced in by Congress for decades is a "gloss on the text" of the executive power vesting clause). While a few might wrongly claim that the Impoundment Control Act of 1974 is unconstitutional, there is no question at all that IEEPA is constitutional insofar as it cut back on presidential power under the Trading with the Enemy Act of 1917 (TWEA). It is also true that the National Emergencies Act of 1976 (NEA) ended all formerly declared presidential emergencies and formalized and curtailed greatly presidential power to declare emergencies.
IEEPA was passed in 1977 to give the power to the President to deal with emergencies requiring trade sanctions or embargoes, like Russia's invasion of Ukraine, or Iran's apparent efforts to build a nuclear bomb. IEEPA does authorize President Trump to impose trade sanctions or embargoes in these situations, but it does NOT delegate to the President the power to raise, lower, defer, and reinstate tariffs, arbitrarily from day to day, on long-standing American allies like Canada, Mexico, and the other countries in the NATO alliance.
The Framers created a unitary executive because they knew that "energy" in the execution of the laws was an essential prerequisite for good government. But when it came to the making of laws or the imposition of taxes, which required popular representation in the legislature, which has the sole power of the purse, the Framers opted for the deliberation-promoting process of bicameralism and presentment to the president set out in Article I, Section 7. As the McConnell/Claybourne amicus brief says:
[The Framers] well understood what Madison called the "mischievous effects of a mutable government," and sought to guard against it by the bicameral structure of Congress. The Federalist, No. 62, at 420 (Jacob E. Cooke ed. 1961). As Madison explained, "It will be of little avail to the people, that the laws are made by men of their own choice, if the laws … be repealed or revised before they are promulgated, or undergo such incessant changes that no man, who knows what the law is to-day, can guess what it will be to-morrow." He posed the question: "What prudent merchant will hazard his fortunes in any new branch of commerce when he knows not but that his plans may be rendered unlawful before they can be executed? What farmer or manufacturer will lay himself out for the encouragement given to any particular cultivation or establishment, when he can have no assurance that his preparatory labors and advances will not render him a victim to an inconstant government?" Id. at 421-22. So, too of American merchants and manufacturers today, whose decisions are affected by the cost of imported goods and materials. It is not an argument for one tariff policy over another to observe the wisdom of the Constitution's assignment of these powers to the branch most likely to pursue a consistent and predictable policy.
The amicus brief is right.
IEEPA is not an ambiguous text on the question of presidential power to impose tariffs/taxes. But even if it were an ambiguous text, and even if some presidential power could be squeezed out of some other statute, tariff/tax decisions of the scale of the ones President Trump has been imposing, delaying, reinstating, raising, and lowering would raise a major question under the Roberts Courts' Major Questions Doctrine set out in cases like Food and Drug Administration v. Brown & Williamson Tobacco Co. (2000) (FDA cannot regulate tobacco as a drug); Alabama v. Ass'n of Realtors v. HHS (2021) (striking down a nationwide moratorium on evictions by landlords during COVID); National Federation of Independent Business v. Dept. of Labor (2022) (striking down a nationwide mandate that employers force workers to get the COVID vaccine); West Virginia v. Environmental Protection Agency (2022) (striking down climate change prevention rules that would have cost over a trillion dollars to comply with); and Biden v. Nebraska (2023) (striking down forgiveness of all student loan debt under a statute which allows that in the event of a terrorist attack). Such major questions must be addressed by Congress and the President under the rules of Article I, Section 7. They cannot be the subject of unilateral presidential action.
To date, the Supreme Court has applied the Major Questions Doctrine to regulatory agencies or cabinet departments, like the Food and Drug Administration, the Department of Health and Human Services, the Department of Labor, the Environmental Protection Agency. In Biden v. Nebraska, the Supreme Court applied the Major Questions Doctrine directly to President Biden himself. Nevertheless, there can be no doubt that President Biden must have been aware of and have approved actions as major as: (1) HHS's nationwide moratorium on evictions during COVID of renters, and of (2) the Occupational and Health Administrations requirement that all American workers be required to get a COVID vaccination, and (3) of the EPA's trillion dollar regulations to fight climate change.
The President is not a King, nor is he above the Constitution that binds the Cabinet Departments and regulatory agencies. Under our Constitution, dealing with major questions—like the imposing, lowering, deferring, and reinstating of tariffs on our NATO allies and on Mexico—is a decision that can only be made by Congress itself acting through bicameralism and presentment as is required by Article I, Section 7. There is no inherent, prerogative power of the President to raise our taxes by unilaterally imposing tariffs on our closest allies and friends of the last 76 years.
