Anne Deysine Analyses US Supreme Court Reversal of Trump Tariffs

PARIS, 23 February 2026 – As the United States grapples with the legal fallout of a landmark Supreme Court decision, renowned French jurist and American studies specialist Anne Deysine has provided critical insight into what she describes as a “major setback” for the White House’s trade policy.

Following the Supreme Court’s ruling on Friday 20 February 2026, which declared Donald Trump’s “reciprocal” tariffs illegal, Professor Deysine has been at the forefront of European academic commentary. Speaking on France Culture at 07:17 this morning, the Emeritus Professor from the University of Nanterre explained that the judiciary has reasserted its role as a check on executive overreach, despite previous concerns regarding the “capture” of the court by radical conservative elements.

A Judicial Check on Trade Policy

The ruling specifically targeted the administration’s ability to unilaterally impose tariffs without sufficient legislative backing. Professor Deysine, author of the acclaimed work Les juges contre l’Amérique : la capture de la Cour suprême par la droite radicale, noted that while the court has a conservative majority, this specific decision highlights the limits of executive power in matters of international commerce.

In her recent interviews, Deysine emphasised that the ruling creates a “legal headache” for the administration. While Donald Trump responded on Saturday by announcing an increase in global customs duties from 10% to 15% “with immediate effect,” Deysine suggests that such moves may face further litigation if they continue to bypass established constitutional frameworks.

Key Profile: Anne Deysine

Impact on International Relations

The implications of Deysine’s analysis extend beyond the Atlantic. With Swiss and European firms now seeking potential refunds for duties paid under the overturned regulations, Deysine’s expertise in “Deregulation by Litigation” provides a roadmap for how international entities might navigate the US court system. She maintains that the Supreme Court remains the “greatest obstacle” to certain executive ambitions, even as the political climate in Washington grows increasingly volatile.

Frequently Asked Questions

Who is Anne Deysine?

Anne Deysine is a prominent French academic, jurist, and professor emeritus at the University of Nanterre. She is widely regarded as one of France’s leading experts on the United States judicial system and constitutional law.

What was the recent Supreme Court ruling regarding Donald Trump?

On 20 February 2026, the US Supreme Court ruled that certain “reciprocal” tariffs imposed by the Trump administration were illegal, asserting that the President had exceeded his authority in implementing these specific trade barriers.

What is Anne Deysine’s view on the current US Supreme Court?

Professor Deysine has frequently written about the “capture” of the court by radical right-wing interests, but she continues to monitor how the institution balances its ideological leanings with constitutional precedents, as seen in the recent tariff reversal.