A former USTR and national security official believes there's a 'decent chance' the Supreme Court will approve Trump's global tariffs.

He's employed them in a novel manner, serving not just as the foundation for his economic agenda, but also as the central element of his foreign policy during his second term.

Import taxes have been employed as a threat to secure ceasefiresfrom countries at war. They've been utilized to coerce countries into pledging greater efforts to stop people and drugs from crossing their borders. They've also been applied, in Brazil’s case, as political leverage due to its judicial system prosecuting a former Trump-allied leader, and in a recent blowup with Canada, as retribution for a television ad.

This week, the Supreme Court hears arguments is examining if the Republican president has exceeded federal law with his numerous tariffs. A ruling against him might restrict or entirely remove the rapid and direct influence that has underpinned much of his foreign policy.

Trump has shown growing frustration and worry regarding the upcoming verdict in a trial he deems among the most significant in American history.

He's stated it would be a “disaster” for the U.S. If the court doesn't reverse lower court decisions that concluded he exceeded his authority by employing an emergency powers statute to implement his tariffs. Trump has indicated he might take the exceptionally rare action of being present for the oral arguments.

In its defense of the tariffs, the Justice Department has emphasized the broad manner in which Trump has employed them, asserting that these trade sanctions fall under his authority in foreign affairs, a domain where judicial review of presidential actions is inappropriate.

Earlier this year, two lower courts and a majority of judges on the U.S. Court of Appeals for The Federal Circuit determined that Trump lacked the authority under the International Emergency Economic Powers Act, or IEEPA to impose tariffs, a power constitutionally vested in Congress. However, some judges who disagreed on the court argued that the 1977 statute permits the president to control imports during emergencies without explicit restrictions.

Tariffs were upheld by the courts pending the Supreme Court's review. Concurrently, Trump has persisted in using them to exert pressure or impose penalties on other nations concerning trade-related and unrelated concerns.

“The fact of the matter is that President Trump has acted lawfully by using the tariff powers granted to him by Congress in IEEPA to deal with national emergencies and to safeguard our national security and economy,” White House spokesman Kush Desai said in a statement. “We look forward to ultimate victory on this matter with the Supreme Court.”

Most presidents haven’t used tariffs as a foreign policy tool

Josh Lipsky, formerly of the Obama White House and State Department and now holding the international economics chair at the Atlantic Council, stated that modern presidents have employed financial sanctions, like asset freezes or trade blockades, rather than tariffs, to achieve their foreign policy and national security objectives.

Presidents possess other legal avenues for implementing tariffs, though these necessitate a lengthy, multi-month procedure to validate the imposed rates.

Citing the IEEPA, Trump acts with greater speed and impact. He issues executive orders establishing new tariffs and uses social media to threaten further import duties, as occurred in late October after he was displeased by a television commercial opposing tariffs from the province of Ontario.

“Presidents have typically treated tariffs as a scalpel, not a sledgehammer,” Lipsky said.

In contrast, Trump has used tariffs as the backbone of his national security and foreign policy agenda, Lipsky said. “All of it is interconnected and tariffs are at the heart of it,” he said.

For example, earlier this year Trump had threatened a 30% tariff on European imports, a major increase from 1.2% before he took office. Seeking to secure Trump’s support for the NATO military alliance and for security guarantees for Ukraine in its war with Russia, the European Union struck a deal to settle for 15% tariffs.

The EU Commission faced criticism from businesses and member states for giving away too much. But Trade Commissioner Maroš Šefčovič argued the settlement was “not only about the trade. It’s about security. It’s about Ukraine.”

Trump has been able “to use it in specific circumstances to get better deals — not just trade deals — but better deals overall than he might otherwise,” Lipsky said. “On the other hand, you would say there’s probably some backlash.”

Supreme Court decision could rattle geopolitics — and wallets

Trump's aggressive tariff tactics have strained ties with both allies and adversaries of the United States. In response, some nations have adopted more protectionist policies or are seeking to strengthen their connections with China, which has tried to be seen as a promoter of free trade.

The financial strain is also a factor. Certain companies have shifted the burden of some of the costs onto customers through price hikes, while others are holding back to observe the final tariff levels.

Tariffs traditionally have been used just as a tool to address trade practices.

“There’s literally no precedent for the manner that President Trump is using them,” said Emily Kilcrease, who was a deputy assistant U.S. Trade representative and earlier worked on trade issues at the National Security Council as a career civil servant during the Obama, Trump and Biden administrations.

“The use of tariffs the way that President Trump is using them is like — just broadscale attack on an economy as a way to incentivize a foreign government to change their posture,” said Kilcrease, now a director at the Center for a New American Security think tank.

But she said the case is not clear-cut. Kilcrease said she thinks there is a “decent chance” the Supreme Court could side with Trump because IEEPA gives the president “broad, flexible emergency powers.”

The Supreme Court, which has so far hesitated to curb Trump's extensive use of executive authority, is also considering this case.

If the court constrains Trump, it could leave foreign governments questioning whether to try to renegotiate trade agreements recently struck with the Trump administration, experts said. But there are political realities at play too, because reneging on deals could affect other foreign policy or economic priorities.

Kilcrease stated that the administration might shift its approach to employ different statutes to validate the tariffs, but this could result in a more intricate and bureaucratic procedure.

“It certainly doesn’t take tariffs off the table,” she said. “It just makes them a little bit slower.”