Keywords: Tariffs, IEEPA, Reciprocal Tariffs, Commerce, Supreme Court, Litigation, Presidential Authority, Trade

The Baldy Center Blog Post 56
Blog Author: Meredith Kolsky Lewis, Professor of Law; Vice Dean for International and Graduate Programs; Director of the Cross-Border Legal Studies Center
Post Title: The Legality of President Trump’s Liberation Day Tariffs

Tariff. A word that has become ubiquitous over the past few years yet remains mysterious to many. Perhaps you had a fleeting familiarity with the word from Ferris Bueller’s droning teacher (“Anyone? Anyone?”) trying to elicit from the class that a cause of significant US inflation and a contributor to the Great Depression was the disastrous Smoot-Hawley Tariff Act of 1930. But by and large even as the US has participated in, removed itself from, and completed various free trade agreement negotiations in recent years, tariffs – the removal of which is a defining feature of such negotiations – have rarely bubbled up to the general public’s notice. In President Trump’s second term, however, the word “tariff” seems to be in the news constantly – even as a verb (which while technically grammatically acceptable is not a usage I had ever seen or heard until recently, notwithstanding having taught, written and read about tariffs for over twenty years).

Why all the sudden attention? President Trump has imposed tariffs in 2025 by using an authority – the International Emergency Economic Powers Act (IEEPA) – that has never before been invoked by a President to impose tariffs – and arguably does not authorize the President to do so. The President can only take action pursuant to IEEPA by, among other things, first declaring a national emergency and conferring with Congress. He can then:

Investigate, block during the pendency of an investigation, regulate, direct and compel, nullify, void, prevent or prohibit, any acquisition, holding, withholding, use, transfer, withdrawal, transportation, importation or exportation of, or dealing in, or exercising any right, power, or privilege with respect to, or transactions involving, any property in which any foreign country or a national thereof has any interest by any person, or with respect to any property, subject to the jurisdiction of the United States. (50 U.S.C. 1702(a)(1)(B)).

President Trump has imposed tariffs pursuant to IEEPA in two different contexts. First, shortly after retaking office, he declared national emergencies tied to fentanyl crossing the Northern and Southern US borders and invoked IEEPA as authority to impose tariffs on Canada, Mexico and China in association with the stated fentanyl emergencies. Second, in April, the President declared a national emergency relating to the US’s persistent trade deficits (in the aggregate, the US imports in more goods from other countries than it exports out). In connection with the latter, President Trump imposed “reciprocal tariffs” on over fifty countries on the basis, amongst other things, that such countries purportedly charge the US higher average tariffs than the US charges them.

The IEEPA tariffs quickly led to dozens of legal challenges in U.S. courts. Most have been stayed (put on hold) while two separate cases are being litigated: one brought by a group of small businesses, and another by 12 State Attorneys General. The former case, Trump v. V.O.S. Selections, challenges the reciprocal tariffs and the latter, Learning Resources v. Trump, challenges both the reciprocal and the fentanyl tariffs. The two cases are now before the US Supreme Court following lower court rulings finding for the challengers. The Supreme Court consolidated these cases for purposes of briefing and oral argument. In addition to receiving briefs from the parties, 44 amicus curiae filed briefs, with 36 in support of the challengers, seven in support of the government, and one supporting neither side. The amici siding with the challengers include both liberal and conservative interest groups.

I am currently writing a book chapter on the United States’ use of unilateral trade measures and have been following the litigation closely. The parties and amici have raised numerous grounds for challenging the IEEPA tariffs, more than can be discussed here. However, of particular note is the fact that the Constitution grants the power to levy tariffs to Congress, not the President. While Congress has delegated some of its Commerce powers to the President through numerous pieces of legislation, the relevant language of IEEPA does not use the word “tariff”, nor any similar wording such as “levy”, “duty” or “tax”. In addition, in statutory provisions in which Congress has delegated authority to the President using words such as duties, tariffs or levies, it has included various precursor requirements such as agency determinations made according to stated investigatory procedures with published notice and comment opportunities. Within this context, two doctrines have emerged, inter alia, to the challengers’ arguments: the major questions doctrine and the nondelegation doctrine.

The challengers argue that the Court’s “major questions” doctrine calls for interpreting IEEPA with an expectation that if Congress wished to delegate to the President largely unfettered power to raise revenue, it would have said so clearly. In the words of the late Justice Scalia, “Congress does not … hide elephants in mouseholes” (Whitman v. American Trucking Associations, Inc., 531, U.S. 457, 468 (2001). 

Similarly, the challengers have invoked the nondelegation doctrine requirement that through its legislative authorizing of an executive agency or the President to use Congress’s commerce power, Congress must set forth “an intelligible principle” to which the grantee of the authority must adhere. While this test has only rarely been applied to find an impermissible delegation of Congressional power, the challengers point out that if IEEPA is to be read to include the power to impose tariffs, the statute contains none of the prerequisites of agency investigations, factfinding, public notice and comment, and limited durations and/or magnitude of such tariffs that appear in statutes in which Congress has used commerce power vocabulary such as “tariffs” or “taxes”.

During the Supreme Court’s nearly three-hour oral argument, the above points seemed to resonate with at least Justices Kagan, Sotomayor and Jackson, with Justice Gorsuch also asking Solicitor General Sauer difficult questions. Justice Barrett also pressed the Solicitor General on the wording of IEEPA and its notable lack of revenue-raising terms.

In support of the IEEPA tariffs, Solicitor General Sauer argued that the above doctrines apply with lesser effect in the context of foreign affairs, and that the IEEPA provides broad powers that should be read to encompass tariffs. Justice Kavanaugh seemed sympathetic to the latter argument, finding it incongruous that Congress intended for the President to be permitted to stop trade altogether under IEEPA but not to be able to impose even a one percent tariff. Sauer had a more difficult time gaining traction with his subsidiary argument that the IEEPA tariffs were not actually “revenue tariffs” because they were intended to apply pressure on trading partners to make deals, not to actually raise revenue. Although the Justices did not mention President Trump’s own rhetoric, one wonders whether they will be dubious of this argument given the President’s statements regarding the amount of money the tariffs will bring into the US Treasury.

Justices Alito, Kavanaugh and Thomas appeared the most sympathetic to the President, and Justices Kagan, Sotomayor and Jackson the most receptive to the challengers’ arguments, with Gorsuch also seemingly leaning in the same direction. Justices Roberts and Barrett were harder to read, asking difficult questions of both sides, though both seemed concerned about the inability of Congress to repeal IEEPA, such that if the Court finds the power exists, Congress likely will be unable to undo it. While most news about the oral arguments signaled skepticism and suggested that the Court would overturn the tariffs, I could see the Court tipping either way.

While the outcome remains to be seen, two things are clear. First, if the Court upholds the tariffs, it will represent an unprecedented – and in my view unwise – blank check for the President to impose tariffs with no meaningful guardrails. Second, if the IEEPA tariffs are struck down, President Trump will almost certainly employ other tools at his disposal to impose other tariffs and continue to pressure other countries to negotiate deals to avoid such levies. Furthermore, although a decision striking down the tariffs would require the government to refund payments, it will likely make the process for seeking refunds slow and difficult – e.g. by requiring substantial documentation. Thus, going forward, consumers are unlikely to see lower prices across the board, and importers may still find their inputs facing tariffs, albeit under different legislative authority.