The Supreme Court’s 6–3 decision limited the president’s use of the International Emergency Economic Powers Act to impose broad tariffs, sparking a fierce dissent from Justice Clarence Thomas who argued history, precedent, and plain statutory text support presidential tariff authority.

The Court’s majority, led by Chief Justice John Roberts, held that IEEPA, a 1977 law, does not authorize the president to impose tariffs even after declaring a national emergency. Justice Thomas, joined by Justices Brett Kavanaugh and Samuel Alito, responded with a scathing dissent that rejects the majority’s reading of both the statute and long-running trade practice. Fox News reported the split, underscoring how sharply the justices diverged on statutory meaning.

Thomas built his argument around historical practice and the text of the statute, focusing on the phrase “regulate … importation” which appears in the law. He argued that phrase had a settled meaning by the time Congress enacted IEEPA. The dissent insisted the word “regulate” has long been understood to include the imposition of duties on imports, and Thomas presented the legal trail to prove it.

“Throughout American history, the authority to ‘regulate importation’ has been understood to include the authority to impose duties on imports.”

Thomas pointed to a concrete line of events: in 1971 President Nixon announced a 10% across-the-board import surcharge, and in 1975 the U.S. Court of Customs and Patent Appeals upheld that move in United States v. Yoshida Int’l. Congress enacted IEEPA in 1977 using virtually identical language shortly after that judicial endorsement. Thomas framed this sequence as clear legislative awareness and continuity in how the phrase functioned.

“The meaning of that phrase was beyond doubt by the time that Congress enacted this statute, shortly after President Nixon’s highly publicized duties on imports were upheld based on identical language.”

Chief Justice Roberts cast the case as a question of extraordinary executive power that demands unmistakable congressional authorization. The majority warned about the president asserting authority to set tariffs with no meaningful limits, and it applied a stringent clarity test to the statute. Roberts wrote that the president must identify explicit authorization in light of the breadth and constitutional context of the claimed power.

“The president asserts the extraordinary power to unilaterally impose tariffs of unlimited amount, duration, and scope.”

“In light of the breadth, history, and constitutional context of that asserted authority, he must identify clear congressional authorization to exercise it.”

Thomas saw that approach as imposing a new and unnecessary clarity hurdle on language that had already operated for decades without controversy. He emphasized that Nixon used the same wording, courts upheld it, and Congress then codified similar terms in IEEPA, so the majority’s fresh standard rewrites the playbook. For Thomas, the majority did not simply interpret language—they created a new rule about how clear Congress must be.

The dissent also tackled separation-of-powers concerns, arguing the nondelegation doctrine has a different shape when it comes to foreign trade. Thomas noted his earlier view that delegations governing private conduct in foreign trade, including duties on imports, fall outside the traditional nondelegation worries. He insisted that applying the usual domestic nondelegation framework to this area misreads both history and function.

“As I suggested over a decade ago, the nondelegation doctrine does not apply to ‘a delegation of power to make rules governing private conduct in the area of foreign trade,’ including rules imposing duties on imports.”

Thomas also flagged Justice Kavanaugh’s separate analysis as reinforcing the statutory interpretation problems in the majority opinion, writing that Kavanaugh “makes clear that the Court errs in concluding otherwise.” That line underscores how the dissent viewed the majority’s approach as a sharp departure from established practice and precedent. The split illustrates a basic disagreement about how to read text in its historical and judicial context.

President Trump responded quickly at a post-decision press conference, announcing a 10% global tariff and stressing the Court “did not overrule tariffs” but “merely overruled a particular use of IEEPA tariffs.” He had warned just a day earlier at a Georgia steel factory that “without tariffs, this country would be in such trouble right now.” The administration framed the move as preserving the policy goal of trade parity and domestic manufacturing even as one legal avenue was constrained.

Trump originally rolled out his tariff strategy in April 2025 as part of a broader push to strengthen manufacturing and encourage reshoring of jobs. The shift to a 10% global tariff signals that the administration intends to keep pressure on trade partners and domestic investment decisions despite the Court’s narrower reading. That political and economic objective remains the same even if the route to reach it will be litigated or legislated anew.

Thomas closed his dissent by insisting the Court’s new standard departs from decades of statutory interpretation and prior judicial treatment, asserting that judges should respect the text and historical practice Congress relied upon. He argued the majority’s approach reads out a meaning that, by long usage, belonged to the executive in matters of import regulation. The point was blunt and direct: the statute said “regulate importation.” Six justices decided that didn’t include regulating importation.