Trump Warns ‘Biggest Threat’ to US Would Be Supreme Court Overruling Tariffs

The Trump administration’s tariff policies are before the Supreme Court.

President Donald Trump looks on during the swearing-in ceremony of U.S. Ambassador to India Sergio Gor in the Oval Office of the White House in Washington on Nov. 10, 2025. Getty Images

President Donald Trump on Tuesday said that national security could be at risk if the Supreme Court rules against his tariffs under an emergency law, arguing that it could pose the “biggest threat” to the United States.

“The biggest threat in history to United States National Security would be a negative decision on Tariffs by the U.S. Supreme Court,” Trump wrote on social media. “We would be financially defenseless.”

Trump then made reference to French President Emmanuel Macron having warned Chinese officials that the European Union may deploy its own tariffs against the country. The Trump administration imposed duties on Chinese imports starting earlier this year.

“Now Europe is going to [use] Tariffs against China, as they already do against others,” Trump said. “We would not be allowed to do what others already do!”

During last week’s oral arguments on the tariff case, some Supreme Court justices appeared to cast doubt on Trump’s authority to impose a broad range of tariffs under the 1977 International Emergency Economic Powers Act (IEEPA).

Justice Amy Coney Barrett suggested it “could be a mess” for the courts to administer refunds to U.S. importers who have paid tariffs that were declared illegal. It remains unclear exactly when the highest court will rule, and whether companies will be entitled to refunds of more than $100 billion in IEEPA tariffs paid so far if the administration loses the case.

Previously, Trump told reporters that the court’s estimates were far too low, and that required repayments would exceed $2 trillion in tariff revenues and investments.

“They’re not giving the right numbers,” the president said last month. “There would be an economic disaster. It would be a national security disaster if we lost the case in the Supreme Court.”

Meanwhile, Trump and Treasury Secretary Scott Bessent have said that there are other ways to impose the government’s tariffs if the Supreme Court case fails, although the president has stressed that the current tariff regime is “more direct” and “less cumbersome” than other methods.

“I have settled 8 Wars in 10 months because of the rights clearly given to the President of the United States,” he said.

Trump has also used tariffs as part of separate negotiations with other countries on a range of issues, including illegal immigration and drug trafficking.

A deal that the Trump administration hashed out with China several weeks ago had lowered tariffs on the country in exchange for its curbing the production of fentanyl precursor chemicals. Earlier this year, tariffs were placed on Mexico and Canada to stem the flow of fentanyl and other drugs, as well as illegal immigration, into the United States.

On the domestic front, Trump said the tariffs could be used to potentially lower or eliminate federal income taxes or provide enough revenue to send out dividend payments worth $2,000 to low- and middle-income families starting next year while paying off the national debt.

On Monday, the president warned that he would place a 5 percent additional tariff on Mexican imports if the country did not immediately provide more water to assist U.S. farmers, while accusing the country of violating a water-sharing treaty.

“As of now, Mexico is not responding, and it is very unfair to our U.S. Farmers who deserve this much needed water,” Trump wrote on Truth Social. “That is why I have authorized documentation to impose a 5 percent Tariff on Mexico if this water isn’t released, IMMEDIATELY.”

Reuters contributed to this report.