WASHINGTON, May 29, 2025 (BSS/AFP) - A US federal court on Wednesday blocked Donald Trump's "Liberation Day" import tariffs from going into effect, ruling that the president had overstepped his authority with the across-the-board levies.

Trump unveiled sweeping tariffs on most trading partners on April 2, with a baseline 10 percent, plus steeper duties on China and the European Union.

He later suspended some of the higher duties pending negotiations with individual countries and blocs.

The three-judge Court of International Trade ruled that Congress did not delegate "unbounded" powers to the president in the International Emergency Economic Powers Act of 1977 (IEEPA) that Trump invoked to justify the tariffs.

"An unlimited delegation of tariff authority would constitute an improper abdication of legislative power to another branch of government," the panel ruled in an unsigned opinion.

The judges said that any interpretation of the IEEPA that "delegates unlimited tariff authority is unconstitutional," according to court documents.

The IEEPA authorizes the president to impose necessary economic sanctions during an emergency "to combat an unusual and extraordinary threat," the bench said.

Trump cited the law when he said trade deficits and the threat posed by Mexican drug cartels justified widespread tariffs.