A three-judge panel of the US Court of International Trade (CIT) yesterday handed down its unanimous ruling following lawsuits brought by a coalition of US states as well as a group representing five small businesses.

The judges rejected the Trump administration’s argument that it had the power to impose the tariffs under the International Emergency Economic Powers Act of 1977 (IEEPA).

Other tariffs imposed on China, Mexico and Canada outside of “Liberation Day” have also been struck down by the court.

The court found: “The worldwide and retaliatory tariff orders exceed any authority granted to the president by IEEPA to regulate importation by means of tariffs. The trafficking tariffs fail because they do not deal with the threats set forth in those orders.”

Oregon’s attorney general Dan Rayfield, who co-led the group of 12 states challenging the tariffs, said: “We brought this case because the Constitution doesn’t give any president unchecked authority to upend the economy.

“This ruling reaffirms that our laws matter, and that trade decisions can’t be made on the president’s whim.”

Jeffrey Schwab, senior counsel and director of litigation at the Liberty Justice Center, which represented the business plaintiffs, said: “We’re delighted by the decision of the Court of International Trade enjoining the president’s so-called ‘Liberation Day’ tariffs.

“This ruling reaffirms that the president must act within the bounds of the law, and it protects American businesses and consumers from the destabilising effects of volatile, unilaterally imposed tariffs.”

The White House has indicated that it will appeal the ruling, which may ultimately end up before the Supreme Court of the United States.

Ireland’s Tánaiste and minister for foreign affairs and trade Simon Harris said: “We note the ruling of the US Court of International Trade in relation to tariffs and also the fact that this ruling is being appealed.

“I want to stress the position once again today that what is required now is for both sides, the EU and the US, to engage in calm and measured dialogue and to do so in good faith.

“The continuing uncertainty over tariffs is the source of serious concern for businesses, here in Ireland but also across the EU and the US — businesses that are concerned about their cost base, their workers, and their plans to invest.

“We will continue to monitor the implications of the court decision in the US while keeping our main focus on the negotiations at hand.”