A coalition of twelve U.S. states filed a lawsuit Wednesday in the U.S. Court of International Trade challenging a series of sweeping tariffs imposed by President Donald J. Trump, arguing that the measures are unconstitutional, lack statutory authority, and are causing widespread economic harm across the country.

The lawsuit, led by the States of Oregon, Arizona, Colorado, Connecticut, Delaware, Illinois, Maine, Minnesota, Nevada, New Mexico, New York, and Vermont, targets President Trump, the Department of Homeland Security (DHS) and its Secretary Kristi Noem, U.S. Customs and Border Protection (CBP) and its Acting Commissioner Peter R. Flores, and the United States government itself. The states are seeking a declaration that the tariffs are unlawful, an injunction blocking their enforcement, and vacatur of related agency actions.

Since February 2025, President Trump has issued a series of executive orders imposing significant additional tariffs on imports from Canada, Mexico, China, and nearly all other trading partners. The orders, justified by the President as responses to various national emergencies—including drug trafficking, border security, and persistent trade deficits—have resulted in tariffs as high as 145% on Chinese goods and a baseline 10% tariff on most other imports. These actions, collectively referred to as the “IEEPA Tariff Orders,” rely on the International Emergency Economic Powers Act (IEEPA) as their legal basis.

The plaintiff states contend that the Constitution grants Congress—not the President—the exclusive authority to impose tariffs and collect duties (Article I, Section 8). They argue that IEEPA does not authorize the President to unilaterally impose tariffs, especially not on the scale and for the reasons cited in the executive orders. The lawsuit asserts that:

• The President’s use of IEEPA to impose tariffs is “ultra vires” (beyond his legal authority) because IEEPA was enacted to restrain, not expand, presidential emergency powers, and does not explicitly grant tariff authority.
• The emergencies cited by President Trump—such as trade deficits and border security issues—do not meet IEEPA’s requirement of an “unusual and extraordinary threat” originating outside the United States.
• The tariffs are not tailored to address the purported emergencies and are instead arbitrary, unpredictable, and economically damaging.

The complaint details significant economic disruption and direct harm to state agencies, public universities, and infrastructure projects:

• Increased Costs: States report immediate and recurring cost increases for imported goods, equipment, and supplies essential to public services, education, and health care. For example, the University of Oregon paid an additional $18,579 in tariffs for a scientific detector system, and Oregon Health & Science University faces a 20% increase in the price of testing kits.
• Market Volatility: The lawsuit cites a 14% drop in the S&P 500 and a 13% drop in the Dow Jones Industrial Average in the wake of the tariff announcements, attributing most of these losses to the new trade policies.
• Budget Uncertainty: State agencies and universities face unprecedented difficulty in budgeting and procurement due to the unpredictability of tariff changes, which can be imposed, modified, or suspended by executive action at any time.

Beyond challenging the President’s authority, the states also allege that Customs and Border Protection’s implementation of the tariffs via its Cargo Systems Messaging Service constitutes final agency action that is both unauthorized by statute and arbitrary and capricious under the Administrative Procedure Act. The states seek to have these actions set aside by the court.

The lawsuit asks the court to:

• Declare the IEEPA Tariff Orders unlawful and void;
• Enjoin federal agencies and officials from enforcing the tariffs;
• Set aside related agency guidance and actions;
• Award costs and attorneys’ fees to the plaintiff’s states.