Today, in Learning Resources, Inc. v. Trump, Nos. 24-1287 and 25-250, the United States Supreme Court held that the International Emergency Economic Powers Act (“IEEPA”), 50 U.S.C. §§ 1701–1706, does not authorize the president to impose tariffs on imported goods. The decision effectively invalidates the sweeping “reciprocal tariffs” and “drug trafficking tariffs” that President Trump imposed beginning in early 2025 on imports from virtually every U.S. trading partner, including tariff rates that reached as high as 145% on Chinese goods. Writing for the court, Chief Justice Roberts applied the major questions doctrine, which is a legal principle requiring federal agencies to possess clear, explicit congressional authorization before issuing regulations on matters of vast economic and political significance. He concluded that the power to “regulate . . . importation” granted by IEEPA does not encompass the distinct and extraordinary power to tax imports, emphasizing that when Congress delegates its tariff authority it does so “clearly and with careful constraints” and that it “did neither” in IEEPA. Justice Kagan, joined by Justices Sotomayor and Jackson, concurred separately on the ground that ordinary statutory construction, without resort to the major questions doctrine, resolved the case: nothing in IEEPA’s text or context enables the president to unilaterally impose tariffs. Justice Kavanaugh filed a dissent, joined by Justices Thomas and Alito, arguing that the phrase “regulate . . . importation” has historically encompassed tariffs, as demonstrated by the Nixon-era tariffs under IEEPA’s predecessor statute (TWEA) and the court’s unanimous 1976 decision in Federal Energy Administration v. Algonquin SNG, Inc., and warning that the decision could generate “serious practical consequences” including the need to refund billions of dollars to importers.

Despite the significance of this decision, its practical impact on tariff policy may prove more limited than its legal implications suggest. As Justice Kavanaugh acknowledged in his dissent, the president retains authority to impose tariffs under numerous other federal statutes that are not affected by today’s decision, though each comes with procedural prerequisites and substantive limitations that IEEPA lacked. These include: Section 232 of the Trade Expansion Act of 1962 (19 U.S.C. § 1862), which authorizes the president to “adjust the imports” of articles threatening national security after a Commerce Department investigation; Section 301 of the Trade Act of 1974 (19 U.S.C. § 2411), which permits the president to “impose duties” in response to unjustifiable foreign trade practices; Section 201 of the Trade Act of 1974 (19 U.S.C. §§ 2251–2253), which authorizes tariffs when imports cause serious injury to a domestic industry; Section 122 of the Trade Act of 1974 (19 U.S.C. § 2132), permitting temporary import surcharges to address balance-of-payments deficits (capped at 15% and limited to 150 days); and Section 338 of the Tariff Act of 1930 (19 U.S.C. § 1338), which authorizes tariffs when foreign countries disadvantage U.S. commerce (subject to a 50% cap). The Trump administration has already announced in response to the decision that it would impose a 10% global tariff for 150 days to replace some of his emergency duties that were struck down. Those tariffs will be imposed under Section 122 of the Trade Act of 1974.

Of note for clients in the steel and aluminum sectors, the existing Section 232 tariffs on steel and aluminum imports, originally imposed by President Trump in 2018 and subsequently modified by the Biden and Trump administrations, are not affected by today’s decision. Those tariffs rest on Section 232 of the Trade Expansion Act of 1962, which the Supreme Court upheld as a valid delegation of tariff authority in Federal Energy Administration v. Algonquin, 426 U.S. 548 (1976) and which the majority opinion today expressly distinguished from IEEPA. Section 232 expressly references “duties” in subsection (a) and requires the Commerce Secretary to conduct an investigation and issue a report finding that imports of the relevant article “threaten to impair the national security” before the President may act. The court today noted these procedural and textual distinctions as evidence that, unlike IEEPA, Section 232 contains the type of explicit authorization and careful constraints Congress has historically attached to delegations of the tariff power. The constitutional validity of Section 232 steel tariffs has been tested—and upheld—through a significant line of litigation. In 2018, after President Trump imposed a 25% tariff on steel imports under Section 232 of the Trade Expansion Act of 1962, the American Institute for International Steel (AIIS) filed suit in the U.S. Court of International Trade challenging the statute as an unconstitutional delegation of legislative power in violation of the nondelegation doctrine. A three-judge CIT panel rejected the challenge in March 2019, holding that the Supreme Court’s 1976 decision in Federal Energy Administration v. Algonquin SNG, Inc., 426 U.S. 548, directly foreclosed the nondelegation argument, though Judge Katzmann concurred with reservations about whether Algonquin remained sound. The Federal Circuit unanimously affirmed in February 2020, with Judge Taranto writing that Algonquin‘s rejection of the nondelegation challenge to Section 232 was “binding precedent” that only the Supreme Court itself could overrule. AIIS then petitioned the Supreme Court for certiorari, but the court denied review on June 22, 2020. As a result, Section 232’s constitutionality as a delegation of tariff authority remains settled law, and the steel and aluminum tariffs imposed under it—now increased to 50% as of June 2025 (with the exception of a 25% rate for the United Kingdom)—are not part of the current IEEPA litigation before the Supreme Court. More recently, in January 2026, an importer filed a new lawsuit at the CIT challenging the methodology CBP uses to calculate Section 232 duties on products made entirely of steel, though this challenge addresses the application of the tariffs rather than the constitutionality of the statute itself. Separately, importers have in prior years obtained company-specific injunctions challenging the extension of Section 232 tariffs to derivative products on procedural grounds, arguing that the original Commerce Department investigation did not cover those products.

Similarly, tariffs previously imposed under Section 301 of the Trade Act of 1974 (including tariffs on approximately $300 billion in Chinese goods originally imposed in 2018–2019) rely on distinct statutory authority and are not invalidated by today’s ruling. Challenges to the Section 301 tariffs on Chinese goods—particularly the Biden-era modifications and expansions—have also been litigated in the CIT. The consolidated CIT proceeding—commonly referred to as In re Section 301 Cases—produced merits rulings that sustained the administration’s authority and (after remand) upheld the agency’s explanations under the APA, leaving the challenged duties in place. The lead appeal proceeded under HMTX Industries LLC v. United States, and on September 25, 2025, the U.S. Court of Appeals for the Federal Circuit affirmed the CIT’s judgment upholding the tariffs, rejecting the key statutory/APA challenges. The lead plaintiffs obtained an extension of time to file a petition for certiorari to February 20, which as of the moment of this writing, had not yet been filed.

Moreover, today’s ruling may itself generate significant new litigation over the process and timeline for refunding the billions of dollars in IEEPA tariff revenues collected from importers since early 2025, which the court acknowledged could be a “mess.” The dissent also flagged the potential for disruption to trade agreements negotiated with countries including China, the United Kingdom and Japan that were facilitated by the leverage of the now-invalidated IEEPA tariffs.

Clients engaged in international trade should be aware that although the immediate effect of the decision is the invalidation of tariffs imposed under IEEPA, the broader tariff landscape remains in flux. The administration may pursue re-imposition of tariffs through the alternative statutory mechanisms described above, may seek new legislation from Congress or may pursue a combination of both approaches. In any event, the procedural requirements of the surviving tariff statutes, including investigation timelines, rate caps and durational limits, will constrain the speed and scope of any reimposition, creating a period of significant uncertainty for businesses with cross-border supply chains. We will continue to monitor developments and are available to advise clients on the implications of this decision for their specific trade and compliance positions.

This client update is for informational purposes only and does not constitute legal advice.