US President Donald Trump threatened 50 percent tariffs on US imports of goods from countries that helped Iran with weapons [File: Evan Vucci/Reuters]
United States President Donald Trump has said imports from countries supplying Iran with military weapons will face immediate 50 percent tariffs with no exemptions, announcing the threatened duty in a social media post just hours after agreeing to a two-week ceasefire with Tehran.
Trump’s Truth Social post on Wednesday did not specify which legal authority he would invoke to impose such tariffs, as the Supreme Court in February struck down his use of the International Emergency Economic Powers Act [IEEPA] to impose broad global tariffs, prompting a lower court to order refunds of some $166bn collected over the course of a year.
The 1977 IEEPA law has been used extensively for decades to back financial sanctions against Iran, Russia and North Korea, but the court ruled that Trump overstepped his authority in using it to impose trade tariffs.
“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! President DJT,” Trump wrote.
However, “it’s a lot more complicated to do that after IEEPA was struck down”, Rachel Ziemba, adjunct senior fellow at the Center for a New American Security, told Al Jazeera. “There’s no immediate policy lever and authorisation that is available for the US to do that. So they need either an act of Congress or need to adapt some other trade tool, and there isn’t really a national security-oriented trade tool.”
Trump did not name any countries that could face punitive tariffs. China and Russia have helped Iran build military capacity to counter US and Israeli pressure, supplying missiles, air defence systems and technology intended to bolster deterrence.
But that support appeared capped during the US-Israeli attacks on Iran. Both Beijing and Moscow have denied supplying any weapons recently, although allegations against Moscow have persisted.
The Reuters news agency has previously reported that Tehran was considering a purchase of supersonic antiship cruise missiles from China. In March, Reuters reported that China’s top semiconductor maker, SMIC, has sent chipmaking tools to Iran’s military, according to two senior Trump administration officials.
“This is a China-related threat, the way I read it. And China will read it that way,” said Josh Lipsky, vice president and chair of international economics at the Atlantic Council.
Although drone and missile parts routinely flow from Chinese entities to Iran, evading US sanctions, Lipsky said Trump was unlikely to follow through with new tariffs in the near term because that would derail his planned trip to Beijing to meet with Chinese President Xi Jinping in mid-May.
“US tariffs on Chinese products have gone down a lot since the court ruling,” said Ziemba, “and slapping on 50 percent tariffs now would be very expensive, especially for US importers and consumers.”
Moreover, with the Trump-Xi meeting looming, “this is kind of an empty threat, but shows that when push comes to shove, Trump comes back to tariffs”, Ziemba said.
Alternative tariff tools
Trump does have active “Section 301” unfair trade practices tariffs on Chinese goods from his first term, to which he may be able to add duties and similar pending cases related to excess industrial capacity and China’s compliance with a 2020 trade deal. But these would require a public notice period before they could take effect.
Trump also may be able to invoke Section 232 of the Cold War-era Trade Expansion Act of 1962, which allows sector-specific tariffs to protect strategic domestic industries on national security grounds, but using this law would require a new months-long investigation and public comments.
Russia has been another source of arms technology for Iran, but US imports of Russian goods have fallen sharply since the invasion of Ukraine in 2022 and the wave of financial sanctions imposed on Moscow as a result.
US imports from Russia, one of the only countries not subject to Trump’s now-cancelled “reciprocal” tariffs, jumped 26.1 percent to $3.8bn in 2025. These are dominated by palladium used in automotive catalytic converters, fertilisers and their ingredients, and enriched uranium for nuclear reactors. The US Department of Commerce is already moving to impose punitive tariffs on Russian palladium after an anti-dumping investigation.