On February 20, the Supreme Court ruled that the International Emergency Economic Powers Act does not authorize the president to impose tariffs, striking down Trump's sweeping country-specific tariffs that had been in place for months. Chief Justice Roberts wrote for the 6-3 majority that while Congress can delegate tariff powers to the president, it must do so with clear and unambiguous language. The ruling applied the Major Questions Doctrine, which requires explicit congressional authorization for actions with major economic or political consequences. Justices Barrett and Gorsuch, both Trump appointees, joined the majority. Justice Kavanaugh wrote the dissent, joined by Justices Thomas and Alito.
Within hours of the ruling, Trump held a press conference calling the decision "a disgrace" and certain justices "fools and lapdogs." He immediately invoked Section 122 of the Trade Act of 1974 to impose a 10% global tariff, then raised it to 15% the following day. Section 122 allows presidents to impose tariffs up to 15% to address balance-of-payments deficits, but without congressional approval, such tariffs expire after 150 days. The ruling did not affect Trump's earlier tariffs on steel, aluminum, lumber, and automobiles imposed under Section 232 of the Trade Expansion Act. US Customs and Border Protection continued collecting tariffs over the weekend while updating systems, creating operational confusion for importers.