The United States Supreme Court has announced it will quickly review the legality of the majority of tariffs imposed under former President Donald Trump, setting a fast-track schedule to hear arguments in the first week of November. The decision has significant global economic and political implications, as the contested import taxes affect trillions of dollars in international trade.

The tariffs, including the so-called “Liberation Day” levies enacted on April 2, 2025, imposed duties ranging from 10% to 50% on imports from various countries. These represented the largest increase in U.S. import taxes since the 1930 Smoot-Hawley tariffs, raising the average applied tariff rate to its highest level in more than a century.

The legal challenge argues that Trump exceeded his authority by imposing these tariffs under the 1977 International Emergency Economic Powers Act (IEEPA), which allows the president to regulate imports during national emergencies but does not explicitly grant the power to levy broad tariffs. The U.S. Court of Appeals for the Federal Circuit ruled 7-4 against Trump’s interpretation, stating that only Congress has the constitutional authority to impose tariffs.

The case also involves tariffs aimed at Canada, Mexico, and China, which were justified by the administration as measures to address fentanyl trafficking. Critics argue the tariffs unnecessarily raise consumer costs, strain trade relationships, and provide limited tangible benefits.

Solicitor General D. John Sauer, representing the administration, contends that the IEEPA grants the president authority to regulate imports broadly, which includes the ability to impose tariffs. The Supreme Court will also consider a related challenge from educational toy companies, ensuring the ruling addresses the legality of the tariffs regardless of the lower court where the case originated.

Opening briefs from the Trump administration are due by September 19, with responses from challengers expected by October 20. Observers note that a ruling in favor of Trump could expand presidential powers, while striking down the tariffs could reduce the U.S. effective tariff rate by at least half and potentially require billions in refunds to importers.