U.S. Ambassador to the United Nations Mike Waltz stated that the U.S. military possesses all necessary resources for the conflict with Iran. However, he also attributed the depletion of military stockpiles to the Biden administration’s extensive arms transfers to Ukraine.
"A significant portion of our stockpiles were diminished not only by the aid provided to Ukraine over the past several years," Waltz told Kristen Welker on NBC News’ "Meet the Press" on July 26. He added that the situation inherited was already strained due to ongoing engagements with the Houthis and the general state of the military under the Biden administration.
Waltz disputed an NBC News report from July 24 suggesting that the U.S. military was rationing munitions and allowing some Iranian attacks to proceed due to declining supplies.
Multiple reports indicate a rapid decrease in U.S. weapons stockpiles amid the Iran war. A May 2026 analysis from the Center for Strategic and International Studies projected that key munitions for the Iran conflict, such as Tomahawk missiles and Patriot and THAAD interceptors, could take three to four years to fully restock.
While aid to Ukraine under the Biden administration did reduce U.S. weapons reserves, defense experts note that the administration had initiated efforts to boost production and replenish these supplies. Between 2022 and 2024, the U.S. transferred substantial quantities of munitions, including artillery shells, anti-tank and aircraft missiles, and Patriot air defense interceptors, to Ukraine and Israel.
"U.S. stockpiles, particularly for advanced air and missile defense interceptors, were already under considerable pressure when the Trump administration took office, with Ukraine aid being a contributing factor," explained Kelly Grieco, a defense policy expert at the Stimson Center. "However, the administration’s own decisions have significantly exacerbated the situation."
Experts also highlighted that many weapons sent to Ukraine were intended for ground combat and have not been directly utilized in the Iran conflict. Mark Cancian, a retired Marine Corps colonel and military specialist at CSIS, pointed out that while approximately 600 Patriot missile systems were sent to Ukraine, leading to a current shortage, and Army Tactical Missile Systems have seen deployment in the Iran war, the U.S. relies on other systems for these engagements. He also stated that munitions provided to Israel, which largely manufactures its own missiles, are not impacting U.S. stockpile shortages.
Biden initiated replenishment of military equipment and scaled up production.
The Biden administration enacted legislation to fund the replacement of weapons transferred to Ukraine. Furthermore, they significantly increased munitions production by awarding billions in defense contracts to expand factory capacity and modernize facilities.
"The Biden administration began the crucial work of expanding our industrial base to meet heightened demand for weapons and munitions," Cancian stated. "The Trump administration has since accelerated these efforts."
Regarding U.S. engagements with the Iran-backed Houthi forces, experts noted that both the Biden and Trump administrations have utilized weapons at a high rate. Under Biden, U.S. forces employed around 200 standard missiles to intercept Houthi and Iranian projectiles, according to CSIS researcher Chris Park. Trump’s month-long bombing campaign against the Houthis likely resulted in the use of dozens of standard missiles, while the Twelve Day War, instigated by the U.S. and Israel against Iran in June 2025, also consumed significant quantities of these missiles.