The Legal Arguments Challenging Trump’s Tariffs: Explained

An initial tranche of cases challenging the Trump administration’s widespread tariffs hinge on similar arguments over illegal use of presidential powers.

The plaintiffs include California Governor Gavin Newsom, the Blackfeet Nation, a Florida company known as Simplified that makes planners, and another in Vermont that makes women’s cycling apparel. They’re all asking courts to decide questions about the proper use of the International Emergency Economic Powers Act to set most of the tariffs, including: Is there a national emergency? Is the statute Trump invoked the appropriate way to impose tariffs? And, does the president have power to set tariffs?

Trump cited IEEPA when he imposed tariffs on China, then Canada and Mexico, then an almost universal 10% tax on imports. The 1977 law authorizes the president to take action in response to a national emergency that presents an “unusual and extraordinary threat.”

The administration pointed to an influx of undocumented immigrants and fentanyl coming over the border as national emergencies when it proposed the tariffs on China, Canada and Mexico earlier this year. Then it cited the US’ trade deficit with many countries as justification for the worldwide tariffs.

The suits argue that IEEPA doesn’t allow for the use of tariffs. They also question the executive’s authority to impose tariffs, pointing to Congress’ taxing authority and limits on the executive branch’s ability to interpret questions of major economic significance.

Here are the issues at the heart of these lawsuits:

‘Unusual and Extraordinary Threat’

The law doesn’t define what the president can call a national emergency—so a key question in the litigation will be whether there was a narrowly construed threat, said Dan Cannistra, a partner at Crowell & Moring.

The plaintiffs in V.O.S. Selections, Inc., v. Trump, who are challenging the worldwide tariffs, say no.

V.O.S. Selections, which imports wine and spirits, said Trump’s “claimed emergency is a figment of his own imagination: trade deficits, which have persisted for decades without causing economic harm, are not an emergency.”

And IEEPA limits the president to actions that are “necessary” to address the given emergency. In Emily Ley Paper Inc. v. Trump, Simplified said Trump’s “China Executive Orders show no connection between the opioid problem and the tariff he ordered—much less that the tariff is ‘necessary’ to resolve that problem.”

Tariffs Under IEEPA

Former presidents have turned to IEPPA for other reasons.

Jimmy Carter used IEEPA to impose sanctions on Iran after the hostage crisis of 1979—a state of emergency that is still in effect. Joe Biden invoked the law to impose sanctions on Russia in 2021. But it has never been used to impose tariffs.

The statute says the president has the power to investigate, regulate or prohibit transactions and transfers involving foreign parties or the importing of currency or securities. But the word “tariff” never appears—“nor does any synonym or equivalent,” V.O.S. Selections said in its complaint.

Richard Nixon used IEEPA’s predecessor, the Trading With the Enemy Act, to set a worldwide 10% import tax in 1971. That move was challenged in court—but Nixon prevailed. After Watergate, Congress trimmed back the 1917 law used by Nixon and passed IEEPA to address non-wartime emergencies. The move came from an impulse to put more checks on presidential authority, Newsom said.

“IEEPA was enacted by Congress as part of a series of reforms to limit presidential authority and to prevent presidential abuse of power,” the California suit said.

An April 7 Congressional Research Service report points out that Congress chose to keep the Trading With the Enemy Act language under which Nixon imposed tariffs when it passed IEEPA.

But between Nixon’s tariffs and Trump’s, “the operative language is the same, and everything else is different,” said Timothy Meyer, a Duke University law professor.

Since 1971, Meyer said, Congress passed IEEPA to limit—not expand—presidential authority. It also passed the Trade Act of 1974, which sets out procedures for the president to impose tariffs.

The Supreme Court’s 2024 Loper Bright Enterprises v. Raimondo decision, and cases decided under the major questions doctrine, also mean the executive branch’s statutory interpretations are viewed very differently now than 50 years ago, Cannistra said.

Presidential Authority

The Constitution gives taxing power to Congress, so without specific delegation of authority, Trump’s tariffs violate the separation-of-powers doctrine, Newsom argued.

“It’s a very, very strong argument,” Meyer said. “It’s very difficult to see what the president is doing with IEEPA as anything other than an end run-around” around what Congress has put in place to delegate certain tariff authority to the president.

The fact that tariff-imposing authority under IEEPA is unclear means the president can’t do it, other plaintiffs argued.

“Presidential authority to unilaterally impose worldwide tariffs, if Congress were to grant it at all, must be granted clearly and unmistakably—not through some implication so vague and indeterminate that it went unnoticed by every other President for nearly five decades,” V.O.S. said.

V.O.S and Simplified both pointed to the major questions doctrine—an idea that’s cropped up in Supreme Court cases recently, under which an agency needs clear regulatory authority to make a high-impact decision.

“Because the Executive Orders present a question of ‘vast economic and political significance,’ the major questions doctrine requires the President to show that the IEEPA ‘clearly’ authorizes him to impose tariffs. The President cannot make that showing,” the Simplified plaintiff wrote.

Read more:

• California’s Newsom Sues Trump Over ‘Chaos’ of Tariff Regime
• Tariff Turmoil Opens Door to Insider Trading Suspicion, Lawsuits
• First Conservative-Leaning Groups Push Back on President Trump
• California v. Trump complaint