The Supreme Court began hearing arguments on Wednesday about the legality of Trump’s sweeping tariffs. The case could redefine presidential control over trade.

Justices questioned whether Trump acted legally under the International Emergency Economic Powers Act (IEEPA). He used this law to impose billions in “reciprocal” tariffs on countries including China, Mexico, and Canada, AFP reported.

The court is deciding if Trump overstepped his authority or acted within his constitutional power to regulate foreign commerce.

Billions at stake

The case involves billions of dollars in customs revenue. It also challenges a key part of Trump’s trade war strategy.

Opponents say IEEPA does not allow broad tariffs. They argue that only Congress can authorize major economic actions. This follows the “major questions doctrine,” which requires explicit legislative approval for major policy decisions.

Trump team defends the president

Solicitor General John Sauer defended Trump. He told the justices that presidents have broad authority to respond to international crises.

“The power to impose tariffs is a core application of such authorities,” Sauer said, according to AFP. He added that tariffs are part of regulating trade, not taxation.

Court decision could reshape power

The conservative-majority court will decide if Trump acted within his powers. The ruling, expected in months, could either protect a key tool of Trump’s economic agenda or limit future presidential authority over trade.

The case does not involve Trump’s tariffs on steel, aluminum, or automobiles, which were issued separately.

Trump’s tariff history

Trump raised the average US tariff rate to its highest level since the 1930s. A lower court ruled in May that he exceeded his authority, setting up the Supreme Court review.

President Trump called the case “one of the most important in US history” and warned of economic consequences if the tariffs are overturned.

Trump skips hearing, officials attend

Trump considered attending the hearing but chose not to. He said he did “not want to distract” from the case. Treasury Secretary Scott Bessent attended, saying he wanted a “ringside seat”. US Trade Representative Jamieson Greer was also present. Bessent said his presence was to stress the economic emergency, not to pressure the court.

Analysts weigh in

ING analysts noted the court rarely overturns presidential actions of this scale. They said the case is unpredictable. “Upholding Trump’s tariffs would shift power from Congress to the President,” they said.

Legal arguments and business impact

The Trump administration says IEEPA lets the president set tariffs and regulate trade. Opponents argue the law does not mention tariffs or taxes. The Constitution gives Congress the power to impose them.

Over 40 legal briefs oppose the tariffs. Only a few support the administration. The tariffs have not caused widespread inflation. But small businesses report higher import costs.

What happens if tariffs are struck down

If the Supreme Court rules against the tariffs, the government could still impose temporary duties up to 15% for 150 days. Officials could explore ways to make tariffs permanent. Countries that already negotiated deals with Trump may avoid reopening talks.