On February 20, 2026, the U.S. Supreme Court delivered one of its most consequential rulings in recent trade history, striking down a sweeping array of President Donald Trump’s tariffs in a 6-3 decision. The cases before the Court centered on a single pivotal question: does the International Emergency Economic Powers Act (IEEPA) of 1977 authorize the president to impose tariffs?

The answer, delivered by Chief Justice John Roberts, was an unequivocal no. Roberts wrote that IEEPA “contains no reference to tariffs or duties,” and that until Trump, no president had ever read the statute to confer such power. The majority held that when Congress grants the power to impose tariffs, it does so clearly and with careful constraints — something IEEPA plainly does not do.

The 6-3 majority was a rare cross-ideological coalition, comprising Chief Justice John Roberts and Justices Sonia Sotomayor, Elena Kagan, Neil Gorsuch, Amy Coney Barrett, and Ketanji Brown Jackson. Notably, three of those six — Gorsuch, Barrett, and Kavanaugh — were appointed to the court by Trump himself during his first term, making the vote a striking rebuke from justices the president had personally elevated. Gorsuch and Barrett joined Roberts in applying the “major questions doctrine,” holding that sweeping executive actions of vast economic significance require explicit congressional authorization.

The three dissenters were Justices Clarence Thomas, Samuel Alito, and Brett Kavanaugh — all conservatives, and Kavanaugh another Trump appointee. Kavanaugh wrote that, despite the “vigorous policy debates” spurred by Trump’s tariffs, those debates are not for the courts to resolve, arguing that tariffs are “a traditional and common tool to regulate importation” within the meaning of IEEPA. Trump praised Kavanaugh effusively after the ruling, quoting his dissent’s observation that the decision might not “substantially constrain a president’s ability to order tariffs going forward.”

Trump responded defiantly. He announced a new 10% global levy under a section of the Trade Act of 1974, signaling that his administration would pursue tariffs through alternative statutory channels. He also pledged a new global tariff of 15%, while pointedly quoting Justice Brett Kavanaugh’s dissent — which noted that the ruling “might not prevent Presidents from imposing most, if not all, of these same sorts of tariffs under other statutory authorities.”

The ruling left the question of refunds unresolved, with potentially $175 billion or more collected under the invalidated IEEPA tariffs — a legal and financial tangle that lower courts will now need to address. Scott Bessent said that it will take time to resolve this issue, but for the time being the Treasury market did not react significantly, while equities rallied.

Trump has finally found out that some of the “checks and balances” on which the US constitutional arrangement is built still exists. He does not have infinite power: the new tariffs can only remain in place for 150 days, before the President needs the authorisation of Congress. The Court effectively clarified that the tariffs are taxes on US citizens and businesses, and that only the Congress has the authority to impose new taxes. “No Taxation without Representation” has been at the basis of the US Constitution since the War of Independence against British rule in 1776.

The question is whether Trump will become more or less aggressive as a result of this ruling, and the answer seems obvious: he will become more aggressive. This does not bode well for the upcoming mid-term elections in November.