The Supreme Court of the United States justices—led by Amy Coney Barrett and Sonia Sotomayor—pressed the solicitor general for the Donald J. Trump administration over his legal basis for sweeping global tariff authority under the International Emergency Economic Powers Act (IEEPA). The exchange came during a highly watched hearing that questioned whether the president can use emergency‑authority law to impose tariffs without explicit congressional approval.

During the hearing, Barrett asked if the statute’s language—authorizing the president to “regulate … importation” of goods—has ever been used historically to justify tariff powers. She said she could point to no precedent in which such wording was seen as granting the power to tax imports. The solicitor general struggled to offer clear historical or statutory analogues. Barrett concluded that the “regulate importation” phrase seemed insufficient to support broad‑based tariff takings. Meanwhile Sotomayor challenged the administration’s framing that these tariffs are not taxes, since they generate revenue for the Treasury. She noted that Congress historically uses the phrase “regulate and tax” together, and questioned whether Congress deliberately omitted tariff‑authority in IEEPA—implying the law was not meant to provide it.

Justices across the ideological spectrum appeared skeptical of the administration’s claim that IEEPA granted such sweeping power. They raised concerns under the “major questions doctrine” — the principle that Congress must clearly authorize policies of vast economic and political significance. Barrett, Sotomayor, and others queried whether granting a president unilateral power to impose global tariffs fundamentally reshapes the balance of power between Congress and the executive.

The outcome of the case could have major consequences. A ruling against the administration may force refunds of billions collected under the tariffs and limit the president’s ability to act unilaterally in trade policy. If upheld, it could set a precedent for significant expansion of executive trade authority. Either way, the hearing underscored how critical the question of tariff power and constitutional authority remains.