Since February 1, 2025, United States President Donald Trump has issued a number of executive orders imposing tariffs on countries around the world, including Canada. As the tariff landscape continues to shift, the number of lawsuits challenging the lawfulness of these tariffs continues to grow. These lawsuits maintain that the tariffs are unlawful and seek to restrain their enforcement.
This bulletin briefly describes the lawsuits and the impact on interested parties.
Background
In response to Canada’s purported failure to curb the migration of illicit drugs into the U.S., President Trump issued an executive order on February 1, 2025, introducing a 25% tariff on all Canadian imports into the U.S. except on Canadian energy or energy resources, which were subject to a 10% tariff. After a month-long pause, those tariffs became effective on March 4, 2025. By another executive order on March 6, 2025, President Trump amended his previous executive order and exempted goods that comply with the Canada-U.S.-Mexico Agreement (CUSMA) and lowered the tariff on potash to 10%.
Similar tariffs exist on goods imported into the U.S. from Mexico, while goods imported from China were subject to a 145% tariff before being temporarily modified on May 12, 2025. The rest of the world is subject to a baseline 10% universal tariff on goods imported into the U.S., with additional amounts varying based on the country at issue, which President Trump also imposed by executive order.
The Lawsuits
Article I, § 8 of the U.S. Constitution assigns the power to “lay and collect Taxes, Duties, Imposts and Excises” to Congress. As President Trump has imposed the tariffs by executive order, their legality depends on whether a congressional statute authorizes him to issue those tariffs. The executive orders primarily invoke the authority of the International Emergency Economic Powers Act, or IEEPA.
On April 3, 2025, Emily Ley Paper Inc. v. Trump was filed — the first known in a series of lawsuits brought by private and state parties challenging the tariffs. These lawsuits primarily argue that the IEEPA does not authorize President Trump to enact the tariffs, seeking declaratory relief that the tariffs are invalid and injunctive relief restraining their enforcement.
See other lawsuits challenging the tariffs
Congress enacted the IEEPA in 1977 as part of a set of revisions to the availability of presidential emergency powers. While the revisions limited those powers in some respects, the IEEPA grants the President certain powers related to international trade following the declaration of a national emergency. The declared emergency must concern an unusual and extraordinary threat to American national security, foreign policy, or economy with a source that is wholly or substantially outside the United States. The President must notify Congress about that declaration of emergency, and Congress may terminate the declaration through a joint resolution. During that national emergency, the IEEPA authorizes the President to engage in certain activities to deal with the emergency, including authority related to the importation of foreign property.
According to the plaintiffs in these cases, such authority does not extend to empowering the President to impose tariffs on imports. Most invoke the principle of American administrative law that when the executive branch claims an authority of major economic and political significance, the statutory basis for that authority must be clear. Since the IEEPA does not mention a power to impose tariffs, and no President has ever invoked the IEEPA to impose tariffs, the plaintiffs argue this standard is not met and the tariffs were made without authority.
A variety of related arguments arise across the different cases. Some contest President Trump’s declarations of emergency, arguing that they do not reflect the type of threat that engages presidential emergency powers under the IEEPA. Others maintain that even if the IEEPA authorizes President Trump to issue the tariffs, the tariffs are still unlawful because the IEEPA represents an unconstitutional delegation of legislative power from Congress to the President.
The government defendants contest each of these claims. They argue that the IEEPA authorizes the tariffs by generally empowering the President during a declared national emergency to “regulate […] importation”, and that this includes a power to issue tariffs. They also maintain that a declaration of national emergency is a non-justiciable political question for the President and Congress rather than the courts to decide, and that the IEEPA contains the minimum “intelligible principle” required to avoid the nondelegation doctrine.
What Can Interested Parties Do?
The cases are still in their early phases, but they are quickly proceeding to their initial determinations. A motion for a preliminary injunction and summary judgment was heard on May 13, 2025, in V.O.S. Selections, Inc. v. Trump before the Court of International Trade, which is a U.S. federal court with special expertise in customs and international trade laws. The same court will hear another motion for summary judgment, this time in Oregon v. Trump, on May 21, 2025.
For cases filed in the federal district courts across the U.S., the government defendants have moved to transfer to the Court of International Trade. On May 22, 2025, the federal district court for the Northern District of California will hear one such motion in California v. Trump.
How the cases advance will likely vary based on the matter and the forum. That said, the rules of the Court of International Trade and the federal district courts contemplate that those with an interest in a case may seek leave to make submissions as amicus curiae that are useful and will not duplicate the submissions of the parties. Although amici do not become “parties” to the litigation in a formal sense, they are represented by counsel and file written briefs supporting a particular outcome.
Interested groups have already obtained leave to make submissions as amicus both on the merits and in the motions to transfer.
Going Forward
The number of proceedings challenging the tariffs is likely to increase, as are the complexities that arise for entities attempting to understand their obligations.
For more information, please contact the authors or any other member of our Litigation & Dispute Resolution or International Trade groups.
