The US supreme court appeared skeptical of the legal basis of the Trump administration’s sweeping global tariff regime on Wednesday after justices questioned the president’s authority to impose the levies.
Justices heard oral arguments on Wednesday morning on the legality of Donald Trump’s tariffs , a crucial legal testof his controversial economic strategy – and power.
Even conservative justices sounded doubtful of the strength of the Trump administration’s position. “The vehicle is the imposition of taxes on Americans, and that has always been a core power of Congress,” said chief justice John Roberts.
In a series of executive orders issued earlier this year, Donald Trump cited the International Emergency Economic Powers Act, or IEEPA, a 1977 law which in some circumstances grants the president authority to regulate or prohibit international transactions during a national emergency, as he slapped steep duties on imports into the US.
The supreme court – controlled by a rightwing supermajority crafted by Trump – is reviewing whether IEEPA grants the president the authority to levy a tariff, a word not mentioned in the law. Congress is granted sole authority under the constitution to levy taxes. The court has until the end of its term, in July 2026, to issue a ruling on the case.
“We don’t contend that what’s being exercised here is the power to tax,” argued Dean John Sauer, US solicitor general, defending the Trump administration in the case. “It’s the power to regulate foreign commerce. These are regulatory tariffs.”
“I just don’t understand this argument,” said liberal justice Sonia Sotomayor. “You want to say tariffs are not taxes, but that’s exactly what they are.”
“I guess I’m wondering whether you also don’t have to contend with the actual purpose of IEEPA,” added liberal justice Ketanji Brown Jackson. The law is “designed and intended to limit presidential authority”, she suggested. “It’s pretty clear that Congress was trying to constrain the emergency powers of the president and IEEPA.”
“I appreciate that, generally, you can look at these words and you can imagine that they mean certain things,” said Jackson. “But here we have evidence that Congress was actually trying to do a particular thing, with respect to the authority that it was presenting to the President. And that thing was not raising revenue.
Conservative justice Brett Kavanaugh told the solicitor general “one problem you have is that presidents since IEEPA have not done this.”
Neal Katyal, the attorney arguing for private companies in the case, said: “Tariffs are taxes. They take dollars from Americans pockets and deposit them in the US Treasury, our founders gave that taxing power to Congress alone.”
He continued, “yet here, the president bypassed Congress and imposed one of the largest tax increases in our lifetimes. Many doctrines explain why this is illegal, like the presumption that Congress speaks clearly when it imposes taxes and duties and the major questions doctrine, but it comes down to common sense. It’s simply implausible that in enacting IEEPA, Congress handed the president the power to overhaul the entire tariff system and the American economy in the process, allowing him to set and reset tariffs on any and every product from any and every country at any and all times.”
Katyal argued against the use of emergencies for a president to implement tariffs.
“I would say the best way of understanding what Congress does in emergencies is to look at their emergency statutes. Not one has ever given the president a taxation power or a tariff power,” he explained. “This is not a wartime or conquered territory statute. This is a use of the statute. They are tariffing the entire world in peacetime. And they are doing it asserting a power that no president in our history has ever had.”
The Oregon solicitor general, Benjamin Gutman, who argued on behalf of states suing the Trump administration over the tariffs, said “the federal government hasn’t identified a single other federal statute that uses the term ‘regulate’ to authorize tariffs or taxes”.
Related: The president who cried tariffs: will the US supreme court challenge Trump’s trade war?
Lower courts have ruled against Trump’s tariffs, prompting appeals from the Trump administration, setting up this latest test of Trump’s presidential power. The supreme court has largely sided with the administration through its shadow docket to overrule lower courts.
Should the supreme court ultimately rule against Trump’s use of IEEPA to impose tariffs, it will force the White House to go back to the drawing board and reconsider how to enforce an aggressive economic policy which has strained global trade ties.
Should the court side with the administration, however, it will embolden a president who has repeatedly claimed – despite warnings over the risk of higher prices – that tariffs will help make America great again, raising “trillions” of dollars for the federal government and revitalizing its industrial heartlands.
Trump himself has argued the court’s decision is immensely important. The case is “one of the most important in the History of the Country”, he wrote on social media over the weekend, claiming that ruling against him would leave the US “defenseless”.
“If we win, we will be the Richest, Most Secure Country anywhere in the World, BY FAR,” Trump claimed. “If we lose, our Country could be reduced to almost Third World status – Pray to God that that doesn’t happen!”
But some of his senior officials have suggested that, if the court rules against their current strategy, they will find another way to impose tariffs. Treasury secretary Scott Bessent, who plans to attend the oral arguments in the case, has said the administration has “lots of other authorities” to do so.
According to the non-partisan Tax Foundation, Trump’s tariffs amount to an average tax increase per US household of $1,200 in 2025 and $1,600 in 2026.
A coalition of 12 states and small businesses, Arizona, Colorado, Connecticut, Delaware, Illinois, Maine, Minnesota, Nevada, New Mexico, New York, Oregon and Vermont, have sued the Trump administration to block the tariffs.
Several other small businesses also filed suit against the Trump administration to block the tariffs. The cases, Learning Resources, Inc v Trump and Trump v VOS Selections, were consolidated by the court.
About 40 legal briefs have been filed in opposition to the tariffs, including from the US Chamber of Commerce, the largest business lobby group in the US.
The US Senate voted 51 to 47 last week to nullify Trump’s so-called reciprocal tariffs, with four Republicans joining Democrats in the vote, though the House is not expected to take similar action.
