President Donald Trump’s novel use of emergency presidential powers to impose new tariffs on Mexico, Canada and China is likely to face legal challenges from opponents, but securing an injunction to stave off the tariffs or a ruling against the president will be an uphill climb, trade lawyers say.

The powers granted under the 1977 International Emergency Economic Powers Act allow the president to implement economic measures to respond to national emergencies. President George W. Bush used the authorities in the wake of 9/11 to freeze assets held by terrorist groups, for instance. During Trump’s first term, he wielded IEEPA to sanction Venezuelan and Iranian entities.

No president has used IEEPA powers to impose tariffs, however, until now.

The closest legal precedent comes from the Nixon administration, when the president used a precursor law to impose an across-the-board tariff. Multiple companies filed suits challenging his use of executive authorities. In those cases, Congress legislated in 1977 to grant Nixon the necessary authority to levy an across-the-board duty before they were determined.

But some trade lawyers see similar legal challenges on the horizon for Trump’s new tariffs.  

Greta Peisch, former general counsel to the Office of the U.S. Trade Representative under President Joe Biden, told Agri-Pulse in an email on Saturday that the president “has broken new ground and is testing the boundaries of trade authorities delegated by Congress.”

Similarly, Peter Harrell, who served in Biden’s National Security Council and the National Economic Council, said in a post to X that Trump’s rationale and legal basis for authorizing a 25% tariff on Mexico and Canada and a 10% tariff on China would “no doubt come up in litigation.”

Several of Trump’s more ambitious policy changes since taking office have been swiftly challenged in the U.S. courts. Last week, a federal judge issued an injunction to temporarily block a spending freeze. A judge in Seattle also blocked enforcement of an executive order limiting birthright citizenship issued on the first day of Trump’s presidency.

But those hoping the courts will stave off the new tariffs could be disappointed, according to Andrew McAllister, a partner at Holland and Knight’s International Trade Group.

“There's some factors that make granting an injunction or something like that potentially difficult,” McAllister said.

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The courts typically only grant an injunction if plaintiffs can prove it is necessary to prevent irreparable harm that might occur while the legality of an action is considered. But the way tariff collection currently works would make that a high bar to clear.

The tariffs collected when an imported product enters the country and is released to the importer are only estimated tariffs. The importer pays them, but then Customs and Border Protection reviews the duty and documentation and comes to a final calculation of the duties owed. This can take many months or, in particularly complex cases, multiple years.

The long runway on tariff collection leaves plenty of time for a president to adjust course and prevent harm, if needed. A court is therefore unlikely to determine that it needs to intervene immediately to prevent irreparable damage, McAllister said.

Even if an injunction is unsuccessful though, opponents will have plenty of opportunities to challenge the constitutionality of the tariffs. The Constitution grants Congress the powers to set U.S. trade policy, which lawmakers then delegate to the executive. Absent legislation codifying Trump’s tariffs into law, lawyers will likely deliberate on whether the president has overreached.

“You can always argue that something's not being used with its intent or [that] the acts are … arbitrary and capricious and beyond the authority vested by the Congress,” Everett Eissenstat, who served as Trump’s deputy director of the National Economic Council, told Agri-Pulse. But here too, opponents may struggle to demonstrate overreach, Eissenstat said.

Congress has already granted the president the power to regulate international commerce in a national emergency. In the case of Mexico, the White House argued in the executive order published Saturday that the inflow of drugs and migrants across the southern border endangered American lives and strained public services. Similarly, the orders for both the Canada and China tariffs cited the harm drug production and trafficking inflict on the U.S. population.

“What's an emergency is such a nebulous, subjective term,” Eissenstat, who is now a partner at law firm Squire Patton Boggs, added. “How are you going to fight?… It's not necessarily a fact-based, numbers thing.”

There are several arguments that could be deployed in a legal challenge though.

The House report that accompanied the 1977 law said that emergencies are “rare and brief, and are not to be equated with normal, ongoing problems,” Harrell noted in recent analysis for Lawfare. But recent presidents have used IEEPA for increasingly expansive reasons.

The language in the IEEPA statute also does not specifically tariffs in its lengthy list of approved emergency responses – although it does include limiting or prohibiting imports.

When presidents have been challenged in the past over their use of IEEPA, however, courts have generally been deferential of presidential authority, Harrell notes.

“We have to view it as a bit of an uphill climb,” McAllister added.

One factor that might undermine the president’s position in a legal fight, McAllister said, is the multitude of reasons Trump and other administration officials have offered publicly for the tariffs.

On Friday, the day before he signed the executive orders, Trump told reporters that there was nothing any of the three countries could do to avert the new tariff actions, calling them “pure economic” and lamenting the large U.S. trade deficits with each country. Trump made similar economic arguments for the tariffs in a Truth Social post on Saturday.  

Vice President JD Vance on Sunday also raised the issue of Canada’s defense spending in pair of posts to X justifying the new duties, arguing it had failed to meet the 2% of GDP spending target for North Atlantic Treaty Organization members.

“It does seem a little bit concerning that they're jumping around in terms of different plausible rationales,” McAllister said. The bulk of IEEPA measures, he added, are issued for a single, very specific reason – like contributing to the war in Ukraine, for example.

“Given that we don't have a lot of precedent here, challengers are going to be trying to poke holes at those things,” McAllister said. “There's going to be lots of things for parties to poke at.”