The US Supreme Court on Friday invalidated President Donald Trump’s sweeping global tariffs, delivering a major legal and political blow to the cornerstone of his economic agenda.
In a 6–3 decision, the conservative-leaning court held that the emergency statute Trump relied upon—the International Emergency Economic Powers Act (IEEPA)—“does not authorize the President to impose tariffs.”
The judgment leaves untouched sector-specific duties imposed separately on imports such as steel and aluminum, as well as other targeted goods. Several ongoing government investigations could still pave the way for additional, narrowly tailored tariffs.
Even so, the ruling represents Trump’s most significant loss before the Supreme Court since his return to the White House last year.
Throughout his political career, Trump has leaned heavily on tariffs as a negotiating tool. During his second term, however, he expanded their use by invoking emergency economic powers to levy duties on nearly all US trading partners.
Those measures included so-called “reciprocal” tariffs tied to practices Washington deemed unfair, alongside additional duties aimed at major partners—Mexico, Canada and China—over concerns ranging from illicit drug trafficking to immigration.
In its reasoning, the court emphasized that “had Congress intended to convey the distinct and extraordinary power to impose tariffs” through IEEPA, “it would have done so expressly, as it consistently has in other tariff statutes.”
Three liberal justices joined three conservatives to affirm lower court rulings that the IEEEPA-based tariffs were unlawful. Conservative Justices Brett Kavanaugh, Clarence Thomas and Samuel Alito dissented.
Delivering the majority opinion, Chief Justice John Roberts observed that “IEEPA contains no reference to tariffs or duties.”
A lower trade court had ruled in May that Trump exceeded his authority by imposing across-the-board levies, blocking most from taking effect. That decision was temporarily paused while the government pursued an appeal.
US business groups welcomed Friday’s ruling. The National Retail Federation said it “provides much-needed certainty” for American companies and manufacturers.
“We urge the lower court to ensure a seamless process to refund the tariffs to US importers,” the federation said.
The justices did not rule on how refunds should be handled. However, Justice Kavanaugh cautioned that the process—acknowledged during oral arguments—could be a “mess.”
EY-Parthenon chief economist Gregory Daco told AFP that the loss of tariff revenues tied to IEEPA could cost the US government about $140 billion.
The decision is expected to lower the average US tariff rate from 16.8 percent to around 9.5 percent, he said prior to the ruling, though he added that any reduction could be short-lived as the government explores alternative legal pathways.
The Yale University Budget Lab similarly estimates that consumers now face an average effective tariff rate of 9.1 percent, down from 16.9 percent, while noting that this “remains the highest since 1946,” excluding 2025.
International reactions were cautious. The European Union said it was reviewing the ruling and would stay in close contact with the Trump administration. United Kingdom officials said Britain would work with Washington to assess the implications for a bilateral trade deal, while Canada said the decision confirmed that Trump’s tariffs were “unjustified.”
Striking down the emergency tariffs “would constrain the president’s ambitions to impose across-the-board tariffs on a whim,” said Erica York of the Tax Foundation.
But she noted that other statutes remain available for imposing tariffs, even if they are narrower in scope or require formal investigations.
“The ruling dismantles the legal scaffolding, not the building itself,” said ING analysts Carsten Brzeski and Julian Geib, underscoring that Trump’s broader trade restrictions could yet re-emerge through different legal routes.
