U.S. Supreme Court strikes down Trump tariffs: UCLA Law expert available for analysis

The U.S. Supreme Court today delivered a landmark 6-3 ruling that President Donald Trump does not have the authority to impose sweeping tariffs under the International Emergency Economic Powers Act (IEEPA). Chief Justice John Roberts, writing for the majority, held that the president must identify "clear congressional authorization" to exercise broad tariff authority - and concluded that no such authorization exists under IEEPA. The cases before the court - Learning Resources v. Trump and V.O.S. Selections v. United States - marked the first time a challenge to a Trump second-term policy received a full Supreme Court hearing.

Professor Kimberly Clausing is available to speak with journalists about the ruling's legal, economic and geopolitical implications.

Kimberly Clausing

Professor Kimberly Clausing is the Eric M. Zolt Professor of Tax Law and Policy at UCLA School of Law and previously served as deputy assistant secretary for tax analysis at the U.S. Department of the Treasury, where she was the lead economist in the Office of Tax Policy during the early Biden administration. Her research examines the interplay between government decisions and corporate behavior in the global economy. She is an expert on international taxation, public finance, international trade and climate policy. She is the author of "Open: The Progressive Case for Free Trade, Immigration, and Global Capital" and has testified before the House Ways and Means Committee, the Senate Committee on Finance, the Senate Committee on the Budget, and the Joint Economic Committee.

In December 2025 testimony before the House Ways and Means Committee, Clausing addressed the legal underpinnings of the tariff regime directly:

"Normally, tax increases are enacted by Congress, which is clearly given authority over all taxes (including tariffs) in the US Constitution (Article 1, Section 8). While Congress has delegated some narrow authority over tariffs to the president with limited exceptions, the majority of current tariff revenue comes from tariffs that rely on the International Emergency Economic Powers Act. For reasons extensively covered in recent Supreme Court briefs, nearly all observers agree that the president's use of tariffs exceeds IEEPA authority. ... Congress should assert control over its power of the purse, including tariff authority."

Her testimony also anticipated the economic stakes of today's ruling, providing one of the most comprehensive pre-ruling analyses of the tariffs' impact on consumers, businesses and workers.

"Trump administration tariffs are the largest tax increase on American consumers in a generation, lowering standards of living for all Americans while generating both economic disruption and a deterioration of US standing in the world."

Email: [email protected]