Trump tariffs face major questions doctrine challenge at Supreme Court

The Supreme Court is weighing whether to expand the president’s powers in a case about Donald Trump’s global tariffs, but fundamental constitutional issues could doom the president’s claim.

The high court raised separation of powers concerns during recent oral arguments over Congress’ lack of a role in Trump’s sweeping trade plan, which Trump said was critical to foreign policy and national security and a matter of “life or death” for the country.

Justices across the ideological spectrum asked Gen. John Sauer, the attorney who argued on Trump’s behalf, questions about whether the president had overstepped his authority. They framed their investigations around two legal principles, at times known as principal questions and nondelegation doctrines, and examined the text of the emergency law that Trump invoked to enact the tariffs.

Judge Clarence Thomas presided over arguments that lasted nearly three hours. On the first question of the day, Thomas, an appointee of President George H.W. Bush, asked Sauer to “spend a few minutes on exactly why the fundamental questions doctrine does not apply to the president in this situation.”

BARRETT AND SOTOMAYOR TAG-TEAM TRUMP LAWYER ON TARIFF POWERS

Under this principle, courts seek to ensure that the executive branch does not use a vaguely written law to carry out an action of great national importance, such as world tariffs.

Sauer said tariffs litigation involving foreign trade agreements is “particularly inappropriate” for applying the principal issues doctrine because courts should give the president broader authority on foreign policy matters.

Brent Skorup, a CATO Institute lawyer who appeared opposite Trump in the case, told Fox News Digital that he sees two trends emerging from the Supreme Court. One is a long-term trend in which the high court has been extremely deferential to the president on overseas matters, but the other, he said, is a more recent use of the substantial issues doctrine.

Courts have increasingly used the doctrine to seek express legal permission for blockbuster policies, as in West Virginia v. EPA and Biden v. He reversed agency actions in the Nebraska cases. Several justices asked whether the same rule would apply if the president, rather than an agency, sought sweeping tariff authority under the law Trump used, which made no mention of the word “tariffs.”

“It’s unclear what trend will emerge,” Skorup said. “My hunch is, and this has been borne out at oral arguments, that most justices probably tend to favor importers, and these newer doctrinal trends will prevail.” He added that he was encouraged by Chief Justice Roberts pressing Sauer on the issue.

“He seemed to think there was a big question here,” Skorup said.

TRUMP REQUESTED THE SUPREME COURT’S IMMEDIATE DECISION ON DEFINITION AUTHORITY, ‘THE DECISION CANNOT BE HIGHER’

A demonstrator holds a sign outside the Supreme Court as the justices hear arguments on President Trump’s global tariff powers on November 5, 2025. (Bill Clark/CQ-Roll Call, Inc via Getty Images)

Trump lashed out this week, highlighting the perceived risks of the trial; This is a sign that he may be prepared for a negative outcome.

Trump claimed that the potential payback could exceed $3 trillion if the tariffs are deemed illegal. He said judges were given “inaccurate figures” on repayment costs.

“It will never be possible to make up for this kind of ‘fooling around,'” Trump wrote on social media. “This would truly become an insurmountable National Security Incident and would be devastating to the future of our Country; Likely unsustainable!”

Trump has used the International Emergency Economic Powers Act of 1977 to circumvent Congress’ role in approving taxes and tariffs, saying the opioid epidemic and trade deficit amount to a national emergency and justifying a series of tariffs on imports from major trading partners from China and India to Canada and Mexico. Trump touted the billions of dollars in revenue the government has collected and said it would be used to pay $2,000 to low-income families and pay off some of the national debt.

TRUMP’S OWN SCOTUS PICKS COULD HURT HIM ON TARIFFS

Justice Amy Coney Barrett and President Donald Trump are shown in a divided image as the Supreme Court considers Trump’s use of emergency powers for worldwide tariffs. (Getty Images)

But the justices repeatedly questioned how Trump could justify bypassing Congress, especially at a time when IEEPA is unclear on the issue. Justices Amy Coney Barrett and Sonia Sotomayor, appointed by Trump and Obama, respectively, challenged Sauer that IEEPA does not clarify that the president can unilaterally enact tariffs, even though it gives the president the authority to “regulate imports.”

The Supreme Court may also, indirectly or directly, incorporate the doctrine of non-delegation into its finding. The basic question is: Even if IEEPA could be read to allow tariffs, would that reading give the President Congressional basic tariff authority without a limiting principle?

Judge Neil Gorsuch, a Trump appointee, seemed particularly interested in the issue and asked Sauer whether Congress “may give the president the authority to regulate commerce with foreign countries as he sees fit.”

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Had the Supreme Court taken the evasion route, it might have interpreted IEEPA narrowly to avoid a possible finding that Congress improperly delegated tariff authority to the president, according to Ilan Wurman, a law professor at the University of Minnesota. Wurman told Fox News Digital that would be easier than directly concluding that Congress ceded constitutional authority to another branch of government.

But Wurman said: “On the other hand, once every century the Supreme Court has to strike something down under the doctrine of nondelegation. Give it a little life here and there, right?”

A decision is expected to be made towards the end of June.