In a sweeping decision with global trade implications, the U.S. Supreme Court has ruled that President Donald Trump exceeded his constitutional authority when he imposed tariffs on Canada, Mexico, China and dozens of other countries under emergency powers.
The majority opinion upheld lower court findings that Trump misused the International Emergency Economic Powers Act, a 1977 law designed to allow presidents to regulate economic transactions during genuine national emergencies. The court found the statute did not authorize broad, countrywide tariffs tied to the emergencies Trump declared.
The tariffs were introduced in two phases. In February, Trump declared a national emergency over fentanyl trafficking into the United States and imposed economy wide duties on Canada, Mexico and China. In April, he declared ongoing U.S. trade deficits a national emergency and launched what he branded “Liberation Day,” triggering so called reciprocal tariffs on much of the world.
Business groups and importers challenged the move, arguing the law makes no specific reference to tariffs as a remedy. They also contended that persistent trade deficits do not meet the threshold of an emergency. The plaintiffs further pointed to the U.S. Constitution, which assigns Congress sole authority over taxes and tariffs.
The Trump administration maintained that the law’s language permitting regulation of imports includes the power to impose tariffs. Trump described the measures as “vital” negotiating tools to secure trade concessions and advance foreign policy goals.
The court’s ruling marks a rare setback for Trump’s broader effort to expand presidential authority. In recent years, the conservative majority has often sided with executive power claims, making Friday’s decision notable.
The immediate economic fallout remains uncertain. Many Canadian and Mexican goods were already exempt under the Canada U.S. Mexico Agreement, which replaced NAFTA. Some countries also negotiated new trade arrangements that reduced or replaced the reciprocal tariffs.
Tariffs imposed under Section 232 of U.S. trade law, targeting industries such as steel, lumber and automobiles on national security grounds, remain intact.
A coalition of business owners known as We Pay the Tariffs reported that presidential tariff revenues reached a record US 175 billion between March and October last year. Many affected importers are now expected to seek refunds from the U.S. government.
For Canada, the ruling removes a layer of uncertainty in cross border trade. For Washington, the decision reinforces the limits of executive authority in shaping global commerce.
