Are Trump’s new tariffs legal? It may not matter.

By Ari Hawkins | 02/03/2025 12:24 PM EST

Donald Trump is the first president to use the International Emergency Economic Powers Act to impose tariffs, teeing up likely legal battles that will test his executive authority.

President Donald Trump.

Donald Trump justified imposing sweeping tariffs on Mexico, Canada and China by pointing to “the major threat of illegal aliens and deadly drugs killing our Citizens, including fentanyl,” which he claims the countries are not doing enough to prevent. Yuri Gripas/ABACA

President Donald Trump’s sweeping tariffs on Mexico, Canada and China may be illegal under the Constitution. But blocking the tariffs in court is likely to be difficult — and time-consuming.

Trump announced Saturday he was levying 25 percent tariffs on goods from Mexico and Canada and a 10 percent tariff on goods from China, under the International Emergency Economic Powers Act, a little-known law passed nearly 50 years ago. It’s the first time a president has ever used the law to impose tariffs, although the measure has repeatedly been used by past administrations to enact sanctions.

Trump’s novel use of the law, however, is likely to spark legal battles that will test the limits of a president’s executive power.

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The International Emergency Economic Powers Act, passed in 1977, grants the president broad authority over economic transactions, and a wide range of abilities to deal with “any unusual and extraordinary threat,” stemming in whole or in part from foreign sources.

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