Ep. 18 – WITA’s Friday Exchange: Knives Out for Tariffs – Dissecting the Supreme Court Debate on IEEPA

A leader in international economic law and procedure, Professor Kathleen Claussen has served as arbitrator, counsel, expert, public servant, and teacher. Her expertise covers several topics of international law, especially economic security, trade, investment, international business and labor; dispute settlement and international dispute bodies; and, administrative law issues surrounding U.S. foreign relations and transnational agreements. Professor Claussen has testified before the U.S. Congress, UK House of Lords, and European Parliament on topics related to U.S. tariff laws and executive power, on which she is a leading authority. In summer 2026, she is a visiting fellow at Campion Hall at the University of Oxford, and for the 2026-2027 academic year, she has been selected to be a Crane Fellow in Law and Public Policy at Princeton University, where she will continue her work as principal investigator of the Economic Agreements Research Network. Professor Claussen’s academic work has appeared in the Yale Law Journal, the Stanford Law Review, the Columbia Law Review, the University of Chicago Law Review, and the Virginia Law Review, among others, as well as in leading international law journals. One of her articles on international investment disputes, The International Claims Trade, was awarded the Smit-Lowenfeld Prize in International Arbitration. She also blogs at Lawfare, Just Security (where she is a member of the Editorial Board), and the International Economic Law & Policy Blog, and is regularly featured on or consulted as an expert for various media outlets such as the Wall Street Journal, Marketplace, Bloomberg, and the Financial Times.

Professor Lederman was Deputy Assistant Attorney General in the Department of Justice’s Office of Legal Counsel from 2009 to 2010, and an Attorney Advisor in OLC from 1994-2002. From 1988 to 2004, he was an attorney at Bredhoff & Kaiser, where his practice consisted principally of federal litigation, including appeals, on behalf of labor unions, employees and pension funds. In 2008, with David Barron, he published a two-part article in the Harvard Law Review examining Congress’s authority to regulate the Commander in Chief’s conduct of war.

Prior to rejoining the Department of Justice, he was a regular contributor to several blogs and web sites, including Balkinization, SCOTUSblog, Opinio Juris, and Slate, writing principally on issues relating to separation of powers, war powers, torture, detention, interrogation, international law, treaties, executive branch lawyering, statutory interpretation and the First Amendment. He served as law clerk to Chief Judge Jack B. Weinstein on the United States District Court for the Eastern District of New York, and to Judge Frank M. Coffin on the United States Court of Appeals for the First Circuit.