Concerns are mounting from Washington, D.C., to Ukraine and Taiwan that the ongoing U.S. conflict with Iran is draining the reserves of advanced weaponry designed to shield American bases, vessels, and global allies from missile assaults. While senior U.S. officials admit to the issue, they are minimizing its seriousness.

Following a barrage of military attacks by the U.S. and Israel that targeted Iran’s Supreme Leader Ayatollah Ali Khamenei and degraded the Islamic Republic’s military strength, Iran has responded with ballistic missile strikes against Israel, U.S. facilities in the region, and various Middle Eastern nations hosting American bases. To protect themselves, U.S. troops and their allies have utilized intricate and costly defense systems that launch interceptors at incoming supersonic warheads—a technical challenge often compared to hitting a bullet with another bullet.

These defensive measures have largely succeeded in neutralizing the majority of Iranian missile and drone swarms. However, Iranian counterattacks have resulted in the deaths of six U.S. service members since Saturday.

Yet, the expenditure of these weapon systems carries consequences that extend beyond the immediate Middle Eastern theater of war. Experts and legislators fear that the rapid depletion of defensive arsenals undermines the U.S. ability to effectively project power against Russia in Ukraine and China in the Pacific.

“I am deeply concerned about Ukraine,” Sen. Richard Blumenthal, a Connecticut Democrat who serves on the Senate Armed Services Committee, tells TIME. “Just as a matter of common sense, our resources and supplies are limited, and I think we will be hard pressed, at some point, to tell Ukraine what is coming.” According to multiple Senators present, inquiries regarding U.S. weapons stockpiles were raised during a confidential briefing on Tuesday between senior Trump Administration officials and Congressional members.

“We understand that a long war … and the intensity of the fighting will affect the amount of air defence equipment we receive,” Ukrainian President Volodymyr Zelensky stated this week, according to reports. “Everyone understands that the right weapons are our lifeline,” Zelensky added. 

On Monday, Trump addressed the anxieties regarding the depletion of weapon stockpiles, posting on Truth Social that munitions reserves are “never been higher or better.” He asserted that the U.S. possesses “a virtually unlimited supply of these weapons. Wars can be fought ‘forever,’ and very successfully, using just these supplies.” Nevertheless, he noted, “At the highest end, we have a good supply, but are not where we want to be.”

When pressed for additional details by TIME, Press Secretary Karoline Leavitt stated on Wednesday, “The United States of America has more than enough capability to not only successfully execute Operation Epic Fury, but to go much further. And we have weapons stockpiles in places that many people in this world don’t even know about.”

While maintaining that the nation’s munitions inventory is abundant, Leavitt attributed any potential issues to former President Joe Biden and his management of Russia’s invasion of Ukraine. “Unfortunately, we had a very stupid and incompetent leader in this White House for four years who gave away many of our best weapons for nothing, for free, to another country, very far away, by the name of Ukraine,” Leavitt remarked.

Ryan Brobst, a specialist on the U.S. defense industrial base at the Foundation for Defense of Democracies, highlighted the U.S. military’s Terminal High Altitude Area Defense System (THAAD) as vital for intercepting Iranian ballistic missiles in recent days. He emphasized that THAAD is especially critical for countering potential Chinese aggression against U.S. assets in Asia. 

“My main concern is not that we don’t have enough munitions to prosecute this conflict with Iran, it’s about the day after and being able to deter China,” Brobst stated. 

Defense Secretary Pete Hegseth addressed worries regarding the Iran conflict’s effect on U.S. armaments on Wednesday, discussing some of the “exquisite” weapons systems employed in the war’s initial phase, such as Patriot air defense missiles. “Our stockpile of those as well as Patriots remain extremely strong,” he told reporters at the Pentagon. “Our air defenses and that of our allies have plenty of runway.” 

Mark Montgomery, a retired U.S. Navy rear admiral, asserts that the impending munitions shortages result from choices made by the last three administrations. “We did marginal to minimal purchases every year and hoped we didn’t get caught out in the open, and we did,” he commented. 

According to Katherine Thompson, a former Pentagon official from the start of Trump’s second term and current defense expert at the Cato Institute, when the U.S. increased weapons transfers to Ukraine to counter Russia’s invasion, it depleted existing inventories without sufficiently boosting industrial production spending to replenish them. Thompson notes that when Biden and Congress authorized large-scale arms shipments to Ukraine, those measures surpassed a prior $100 million cap on drawing from U.S. stockpiles for allies. “To be fair to the Trump Administration, they inherited this problem from mass draw downs of U.S. stocks,” she observes.

The extensive domestic policy package Trump enacted last summer allocated roughly $150 billion for military and national defense spending. However, Thompson notes that these funds were not designated for augmenting overseas supplies of THAAD or Patriot missiles.

Brobst suggests that the solution lies in buying more munitions and securing multi-year contracts to encourage manufacturers to invest in expanding production capacity. “The root cause of this shortage is the fact that successive administrations failed to procure the necessary number of interceptors over many years. This led to production lines slowing down or even shuttering.”

The Pentagon has initiated measures to boost output, such as signing a framework agreement with Lockheed Martin in January to quadruple THAAD production over the next seven years, rising from 96 to 400 interceptors annually. Additionally, the U.S. recently revealed plans to collaborate with defense contractor L3 Harris to enhance the manufacturing of essential propulsion systems for these missiles. However, the effects of these actions will not be immediate.

Trump is scheduled to meet with defense industry executives later this week, with stockpile issues expected to be on the agenda. 

“This is what happens when the President and Congress willfully remove restraints on U.S. stocks,” Thompson concludes. “That should never have been done and these are the consequences for it.”