The Supreme Court ruled Friday that President Trump’s sweeping global tariffs are illegal, delivering the most significant legal defeat of his second term and undercutting a central White House trade initiative.

Chief Justice John Roberts wrote for a 6–3 majority that Trump exceeded his authority by invoking emergency powers to impose duties on virtually every country. The tariffs at issue were expected to raise about $1.5 trillion over the next decade—representing roughly 70 percent of Trump’s second-term levies, according to the Tax Foundation.

Chief Justice John Roberts was joined by Justices Sonia Sotomayor, Elena Kagan, Neil Gorsuch, Amy Coney Barrett and Ketanji Brown Jackson in the majority. Justices Clarence Thomas, Samuel Alito, and Brett Kavanaugh dissented.

The ruling is the first time the high court has definitively struck down one of Trump’s second-term policies. In other areas, the court has granted Trump broad latitude to deploy executive power, but a majority of justices said he went too far in enacting his most sweeping tariffs without clear authorization from Congress.

Trump imposed the tariffs in two waves. In February 2025, he placed 25 percent duties on most Canadian and Mexican imports and 10 percent on Chinese goods, citing fentanyl trafficking. Then in April, on what he dubbed “Liberation Day,” he imposed a general 10 percent tariff on imports from nearly all countries and steeper rates on nations the administration deemed trade violators.

Trump declared overdose deaths from fentanyl and persistent annual trade deficits to be national emergencies that justified the new trade policy under the International Emergency Economic Powers Act, a 1977 law Congress passed to give presidents tools for responding to foreign crises.

The court rejected that argument. “Had Congress intended to convey the distinct and extraordinary power to impose tariffs, it would have done so expressly,” Roberts wrote. The court noted that no president in IEEPA’s history had invoked the statute to impose tariffs before Trump.

The decision leaves unresolved whether importers are entitled to refunds. Kavanaugh warned in dissent that the refund process was likely to be a “mess.”