On September 21, 2020, President Trump signed Executive Order 13949, authorizing the Treasury Department to identify, designate, and block the property and assets of individuals and entities involved in Iran's conventional arms activities. The executive order delegated to the Treasury's Office of Foreign Assets Control (OFAC) the authority to determine who qualifies for sanctions based on involvement in Iranian arms sales and transfers. Once designated, all U.S. persons and entities are prohibited from conducting financial transactions with the sanctioned parties, and any assets held within U.S. jurisdiction become frozen.

The practical effects extend to American businesses, financial institutions, and individuals with international dealings. U.S. companies engaged in trade or finance involving designated Iranian arms actors face criminal and civil penalties for violations. Banks and payment processors must screen transactions to ensure compliance, creating compliance costs throughout the financial system. Americans with family or business connections to Iran face restrictions on money transfers and financial support. The order also restricts U.S. persons from providing services or goods to designated entities, effectively banning participation in any supply chain involving sanctioned arms activities.

This order represents a significant expansion and acceleration of Iran sanctions policy established years earlier. It follows the pattern established by the Trump administration's maximum pressure campaign against Iran, including the 2018 withdrawal from the nuclear accord and subsequent economic sanctions. The related continuation of the national emergency declaration regarding Iran in March 2026 maintained these authorities, while the February 2026 Executive Order 14382 addressing Iranian government threats further consolidated executive power to impose restrictions. The April 2026 troop deployment to enforce a maritime blockade and the expedited $8.6 billion arms deals to Mideast partners demonstrate an escalatory posture, using sanctions against Iran paired with military buildup and arms sales to regional competitors.

No significant court challenges to the executive order's validity have been documented, though its application remains subject to administrative law constraints. The order represents an exercise of executive authority under the International Emergency Economic Powers Act, which provides the president broad discretion during declared national emergencies. Reversing this action would require either presidential rescission or congressional action through statutory amendment, neither of which occurred under subsequent administrations.