Supreme Court strikes IEEPA tariff power, elevates USTR authority
In brief
- Supreme Court ruled 6-3 in Learning Resources v. Trump that IEEPA tariffs were unconstitutional
- USTR now leads tariff policy through Section 301, requiring formal investigations and public comment
- Ambassador Greer launched 15+ country investigations in March 2026, reshaping US trade strategy
- New alternative tariffs face potential legal challenges within months
The Court's Core Holding
The Supreme Court determined that tariff authority belongs to Congress, not to the executive branch operating under vaguely defined emergency powers. The IEEPA tariffs were unpredictable by design. They could appear overnight, targeting any country or product category with minimal warning. That opacity created friction across markets and trading partners alike.
The ruling eliminates the legal foundation for tariffs imposed via emergency proclamation. In its place, the USTR is now running the show through Section 301 of the Trade Act of 1974, a more traditional and legally grounded mechanism for investigating and responding to unfair trade practices.
USTR's New Authority and Scope
Ambassador Jamieson Greer, the US Trade Representative, now leads tariff policy under this statutory framework. The shift carries real operational weight. Section 301 investigations require formal processes, evidence gathering, public comment periods, and bilateral negotiations. These steps take time and create visibility.
Ambassador Greer has already initiated multiple Section 301 probes involving over 15 countries and the European Union, with investigations centered on forced labor and other trade violations. The March 2026 initiation of Section 301 probes across more than 15 countries represents one of the most ambitious trade investigation campaigns in recent memory.
Timeline and Predictability
With the shift to Section 301 investigations, the timeline for new tariffs becomes more transparent. Probes take months. Negotiations take longer. This contrasts sharply with the overnight tariff deployments that characterized IEEPA authority.
President Trump announced alternative tariffs of 10-15% on global imports following the ruling, leveraging different statutory authorities. Some trade lawyers expect cases targeting these new tariffs under Section 122 of the Trade Act to reach the courts within months. The legal battles aren't over. They've simply moved to a new arena, one where statutory language and congressional intent matter more than emergency declarations.
