By Jonathan Lord and Andrea Kendall-Taylor 

Last month, both the U.S. and French navies intercepted cargo vessels smuggling thousands of weapons from Iran bound for Yemen. Tehran sent the shipments in defiance of a U.N. Security Council resolution banning the provision of weapons to the Houthis, Iran’s Yemeni partner and proxy force in the civil conflict.

The two seizures alone netted thousands of Russian-style assault rifles and machine guns, dozens of antitank missiles, and over half a million rounds of ammunition. Likewise, last summer, the British navy snagged an Iranian vessel carrying surface-to-air missiles and engines for land-attack cruise missiles.

Instead of allowing these weapons to gather dust, Washington should send them to Ukraine.

The U.S. Central Command (Centcom), through its work with European allies and Gulf partners, is well on its way to turning the critical waterways around the Arabian Peninsula into a panopticon, making it increasingly difficult for the Islamic Revolutionary Guard Corps navy to operate without detection.

The U.S. Naval Forces Central Command’s Task Force 59 has blazed the trail of innovation in maritime domain awareness, which has enabled more and more seizures of smuggled Iranian weapons at sea. Its success in stymying Iran has left Centcom with vast stores of seized weapons. These weapons, once inspected and recorded by the United Nations as evidence of Iran’s violations of U.N. Security Council resolution 2624, are housed in U.S. military facilities across the region.

It’s time to put these weapons in service to a good cause: supporting Ukraine. The Defense Department and NATO allies have mobilized to deliver various weapons to Ukraine, everything from rifles to rockets, and soon tanks. In January, the Pentagon went so far as to raid its weapons stockpile in Israel for artillery shells to support Kyiv. And the need is not going away.

The Pentagon is scrambling, for example, to boost its production of artillery shells by 500 percent within two years, all the while storing thousands of usable Iranian munitions. While these captured Iranian weapons will not fill every requirement of the Ukrainian army, many would certainly help as it approaches the first anniversary of defending its homeland against Russia’s illegal and brutal invasion.

Beyond filling immediate military necessities, the transfer of these weapons would have other positive knock-on effects. Sending Iran’s weapons to Ukraine for use against Russia could drive a wedge between Moscow and Tehran at a moment when their interests are converging. Iran has trained and equipped the Russian military with loitering munitions, which the Russians have unleashed on Kyiv’s civilian infrastructure, in a blatant effort to leave Ukrainians in the dark and cold this winter.

Russia and Iran have colluded to evade sanctions, trade and resist the West’s attempts to constrain their respective efforts to destabilize Europe and the Middle East. Turning Iran’s weapons back on Russia might drive Moscow to pressure Tehran to stop smuggling weapons to Yemen, particularly as more and more shipments are intercepted.

Additionally, the transfer of these weapons could also give ammunition to Ukraine in the information war. Volodymyr Zelensky’s government has demonstrated tremendous aptitude for info operations and could easily find innovative ways to translate Iranian weapons not just into battlefield victories but also into public messaging ones as well.

Legal obstacles may exist that prevent President Biden from treating these seized Iranian weapons as U.S. stocks and simply authorizing their transfer under Presidential Drawdown Authority, as he has done 31 times so far since August 2021. But if these weapons are technically still the property of Iran, the president should waste no time in seeking legal action to seize them under U.S. civil forfeiture authorities.

The Biden administration and its European allies have already demonstrated tremendous creativity in applying new policy tools in support of Kyiv. Biden could, for example, request legal authorities from Congress to enable this transfer of arms. Already, the Biden administration secured congressional support to allow Washington to send the seized assets of Russian oligarchs to support Ukraine’s reconstruction. Congress would welcome the opportunity to find new, low-cost avenues to support Ukraine — and would likely jump at the chance to poke Moscow in the eye with Tehran’s finger.

Last year, the Biden administration debuted a National Security Strategy that seeks to marshal the resources of the United States, with those of its partners and allies, to defend the rules-based order. Iran and Russia are prime offenders that have sought to bully their way to greater power and influence through the brutalization of their neighbors.

While these two pariah-states deserve each other, there’s poetic justice in turning their malign activities back on them. Sending Iran’s weapons to Ukraine advances the mission in ways both tangible and symbolic. Washington should move without delay.

Jonathan Lord is a senior fellow and director of the Middle East security program at the Center for a New American Security. Andrea Kendall-Taylor is a senior fellow and director of the transatlantic security program at the center.