The Supreme Court ruled in a 6-3 decision on Friday to overturn President Donald Trump’s comprehensive import tariff agenda, delivering a blow to the president’s signature economic strategy, according to AP News.

The case, which had originally been brought forth by a group of small businesses, prompted the highest court to consider whether a 1977 emergency powers statute granted the executive the authority to impose tariffs.

The president sharply criticized the supporting justices, two of whom were Justice Amy Coney Barrett and Justice Neil Gorsuch, whom he had appointed.

“The Supreme Court’s ruling on tariffs is deeply disappointing,” Trump said in a press conference Friday afternoon. “I’m ashamed of certain members of the court, absolutely ashamed for not having the courage to do what’s right for our country.”

Although the International Emergency Economic Powers Act, or IEEPA, had been used by previous presidents to regulate importation under certain conditions, the Trump administration was the first to invoke the law to administer tariffs. The majority’s opinion, penned by Chief Justice John G. Roberts Jr., reasoned that Trump’s unilateral tariff policies were unconstitutional because the power of taxation belongs solely to Congress.

“The Framers did not vest any part of the taxing power in the Executive Branch,” Chief Justice Roberts wrote in his opinion.

Justices Brett Kavanaugh, Clarence Thomas and Samuel Alito dissented, arguing on behalf of the tariff policy’s legality.

“The tariffs at issue here may or may not be wise policy,” Kavanaugh wrote. “But as a matter of text, history and precedent, they are clearly lawful.”

Neal Katyal, the attorney representing the small businesses that brought the case, identified Friday’s outcome as a “complete and total victory.”

“It’s a reaffirmation of our deepest constitutional values and the idea that Congress, not any one man, controls the power to tax the American people,” Katyal said in a statement.

The decision may force the administration to reimburse the thousands of U.S. businesses that had imported goods throughout Trump’s second presidential term. Such refunds, reflecting the government’s accumulated tariff revenue, would amount to more than $100 billion in total, according to The New York Times. Many companies, including Costco, have already approached lower courts seeking such refunds.

Justice Kavanaugh warned that any sort of reimbursement process would be “a mess.”

Despite the ruling, members of the Trump administration have voiced commitments to pursuing other legal routes to uphold the global tariffs.

“[The justices’] decision is incorrect,” the President said. “But it doesn’t matter because we have very powerful alternatives.”

Shortly following the decision, the administration announced plans to enact a new sweeping 10% tax on imports, reported NBC News. The president cited his powers as established in the Trade Act of 1974 as justification for the move. Less than a day later, he announced an increase in the global tariff to 15%.

The 1974 law stipulates that, once enacted, such tariffs can only last up to 150 days. After that deadline, members of Congress may have to pass legislation to extend them.

The newly enacted measure highlights Trump’s commitment to tariffs, a strategy that has defined his economic policy agenda since the campaign trail. 

Many will likely maintain a renewed focus on the administration’s developing tariff policy in light of the Supreme Court’s most recent act of defiance against the president.