WASHINGTON — President Trump on Wednesday threatened to impose massive 50% tariffs on countries sending military firepower to Iran, putting Russia and China on notice.

“A Country supplying Military Weapons to Iran will be immediately tariffed, on any and all goods sold to the United States of America, 50%, effective immediately. There will be no exclusions or exemptions!” Trump wrote in a signed Truth Social post.

The threat comes weeks after the Supreme Court took a sledgehammer to Trump’s favorite tool to impose customized tariffs — the International Emergency Economic Powers Act — was shut down by the Supreme Court.

US President Donald Trump holds a press conference on Iran.

A Iranian cluster munition is fired towards Tel Aviv on April 8, 2026. Getty Images

Trump has since turned to other tariff authorities to re-up many of the duties he imposed under IEEPA, but it’s not entirely clear what law he’d be using to fulfill his Wednesday threat.

Donald Trump speaking at a press conference.

President Trump threatened to impose tariffs on countries supplying Iran with weapons. Anadolu via Getty Images

Avi Ohana and Mazal Amrani stand in their destroyed living room and kitchen.

A couple looks at their destroyed home in Beit Shemesh, Israel on April 5, 2026. Getty Images

The alternative tariff authorities Trump used have been much more cumbersome than IEEPA and difficult to impose customized rates.