Ukraine and its European partners are waiting to see how the war in Iran will affect US military aid — particularly the supply of Patriot air defense missiles that Kyiv depends on to intercept Russian ballistic strikes, Foreign Policy reports in a piece by Sam Skove, a staff writer covering transatlantic relations.
"Everything will depend on the situation around Iran," one European diplomat told the publication.
How PURL works — and where it falls short
The United States began supplying Ukraine with Patriot interceptors designed to shoot down ballistic missiles in April 2023. In July 2025, the Trump administration ended free transfers and began selling the missiles to NATO states, which then pass them on to Ukraine. The mechanism is called the Prioritized Ukraine Requirements List (PURL), and weapons sent through it come either directly from US stockpiles or are built from scratch, according to Foreign Policy.
The system has not closed the gap. President Volodymyr Zelenskyy has repeatedly complained about a shortage of interceptors. Andrius Kubilius, the European Commissioner for Defense and Space, said in March that Ukraine needs up to 2,000 Patriot missiles per year, while Kyiv has received only 600 interceptors over four years.
According to Yasir Atalan, deputy director at the Center for Strategic and International Studies (CSIS), the missiles' interception rate has fallen to around 25%, partly because Russia has adapted to them. That figure could fall further if Washington halts deliveries entirely, Foreign Policy notes.
How Iran drained the stockpile
Since the war with Iran began on 28 February 2026, the United States has used close to half its Patriot stockpile — an estimated 2,330 units — defending against Iranian ballistic missiles, the magazine reports. More may be needed: although the war appears stalled, Tehran reportedly retains at least half its missile launchers, meaning a renewed campaign would draw further on US supplies.
The missiles are also in demand for US forces elsewhere, including for defending Taiwan against a potential Chinese invasion, the publication notes — further squeezing the pool available to Ukraine.
Scaling up production offers no quick fix. CSIS data cited in the article puts the current lead time on the newest Patriot variant, the PAC-3 MSE, at roughly 42 months from contract to delivery, while the US produces fewer than 200 units per year.
Already-paid weapons safe; future packages uncertain
A diplomat from a PURL participant country and a second senior European diplomat told Foreign Policy that the US has assured partners weapons already paid for under PURL will be delivered. What comes after that is less clear. The senior European diplomat expressed doubt about further packages given competing US needs.
Signals from the Trump administration have offered little reassurance. On 14 April, US Vice President JD Vance said the halt in military aid to Ukraine was one of the steps the White House is "most proud of."
Trump may also be using PURL itself as leverage, the article argues. He has repeatedly threatened to cut aid because Kyiv is acting "uncompromisingly," and reportedly warned he would shut down PURL if European countries did not join the US in countering Iranian control of the Strait of Hormuz.
European alternatives fall short
Ukraine is developing its own missile defense system, which it hopes to field by the end of 2027, but the technology is difficult to manufacture. The closest European equivalent, SAMP/T, is produced at a rate of 300 interceptors or fewer per year — well below the 2,000 Kubilius said are needed. Zelenskyy has previously noted shortages of interceptors for the SAMP/T systems Ukraine already operates and said Patriots are more effective.
Some grounds for optimism remain, according to Foreign Policy. Trump appears to enjoy the arrangement under which Europeans pay the US for weapons Ukraine needs and brings it up frequently in press appearances. Europe also has the funds to buy after the approval on 23 April of a $106 bn aid package for Ukraine. The package incentivizes buying weapons in Europe but allows exceptions for systems only available outside the continent — Patriots among them — leading at least some Europeans to conclude Trump is unlikely to walk away from the program.
"Ukraine has to be reckoned with"
Ukrainian resilience may be a quality some in the US administration are not factoring in.
"Sometimes when I talk to [American] officials, they see Ukraine as a state that won't last a day or two without international support. But I think Ukraine has proven time and again — on the battlefield, in politics, in social life… — that it must be reckoned with," the PURL country diplomat said.
The Pentagon recently freed up $400 mn earmarked for military aid to Ukraine that had previously been blocked within the US Department of War, though delivery timelines have not been set.
