The United States Supreme Court is expected to rule on a case about the legality of President Donald Trump’s tariffs.

The high court on Tuesday added a non-argument/conference date on its website, indicating that it could release its ruling, although the court does not announce ahead of time which rulings it intends to issue.

The challenge to Trump’s tariffs has been one of the most closely watched cases on the court’s docket amid the broader impact on the global economy.

In a social media post on Friday, Trump said such a ruling would be a “terrible blow” to the US.

“Because of Tariffs, our Country is financially, AND FROM A NATIONAL SECURITY STANDPOINT, FAR STRONGER AND MORE RESPECTED THAN EVER BEFORE,” Trump said in another post on Monday.

However, data on this is mixed. The US gross domestic product (GDP) grew by 4.3 percent in the third quarter of 2025, marking the biggest increase in two years. Meanwhile, US job growth has slowed, with sectors heavily exposed to tariffs seeing little to no job growth.

“Jobs in sectors with higher import exposure grew more slowly than jobs in sectors with lower import exposure, suggesting tariffs may have weighed on employment,” Johannes Matschke, senior economist for the Kansas City branch of the Federal Reserve, said in an analysis in December.

Legal arguments

Trump invoked the International Emergency Economic Powers Act (IEEPA) in February 2025 on goods imported from individual countries to address, what he called, a national emergency related to US trade deficits.

Arguments challenging the legality of the decision began in November. At the time, the court’s liberal and some conservative justices had doubts about the legality of using the 1977 act.

Justice Neil Gorsuch, whom Trump appointed during his first term, was among those sceptical.

“Congress, as a practical matter, can’t get this power back once it’s handed it over to the president,” Gorsuch said at the time.

Chief Justice John Roberts told Solicitor General D John Sauer, who argued on behalf of the administration, that imposing tariffs and taxes “has always been the core power of Congress”.

The act grants broad executive authority to wield economic power in the case of a national emergency.

The matter reached the Supreme Court after the lower courts ruled against the Trump administration, finding that the use of the law exceeded the administration’s authority.

Among the courts that ruled against the White House was the Court of International Trade. In May, the New York court said that Congress, and not the executive branch, has “exclusive authority to regulate commerce”. This decision was upheld in a Washington, DC, appeals court in August.

Legal experts believe it is likely that the high court will uphold lower court decisions.

“My sense is that, given the different justices’ concerns, the Supreme Court will decide that IEEPA does not provide the ability for the Trump administration to adopt the tariffs,” Greg Shaffer, a law professor at Georgetown University, told Al Jazeera.

If the Trump administration were to lose the case, the US would need to refund some of the tariffs.

“It [ruling against the administration] would mean that those who paid tariffs that were imposed illegally would have to be reimbursed. I would think that that would be the outcome,” Shaffer added.

In September, Secretary of the Treasury Scott Bessent said on NBC’s Meet the Press that the US would “have to give a refund on about half the tariffs”.

The Trump administration has said that if the Supreme Court does not rule in its favour, it will use other statutes to push through tariffs.