<h1>25% extraterritorial tariff on imports from countries trading with Iran challenges executive authority, risks refunds and trade disruption</h1> A new executive-imposed 25% tariff targeting imports from countries that trade with Iran institutes an extraterritorial punitive trade measure intended to coerce Iran by reducing its access to foreign goods and thereby increasing domestic prices in Iran. The instrument's legal basis is unspecified but appears to contemplate use of IEEPA; uncertainty over authority and whether the tariff will be layered atop existing ad valorem duties creates immediate legal and administrative ambiguity, and ongoing litigation challenging prior tariff actions could lead the Supreme Court to invalidate the measure and mandate refunds to affected importers. The tariff also produces operative domestic effects by raising U.S. import costs from Iran's trading partners and risking disruption of recent trade détente with China.