As the United States temporarily halts its conflict with Iran, questions arise regarding President Trump's military resources.

Earlier this month, at the Pennsylvania Defense and Innovation Summit, President Trump, flanked by leading defense industry CEOs, delivered a clear directive: accelerate weapons production. "We have the best quality in the world," Trump declared to the arms manufacturers at the US Army War College, with 'Secretary of War' Pete Hegseth by his side. "But we need a little more speed."

The Trump administration presented the summit as a dual strategy to invigorate American industry and enhance US warfighting capabilities, bolstering what Hegseth termed its "arsenal of freedom." However, largely unaddressed was the substantial expenditure of sophisticated and complex-to-manufacture weaponry during nearly 40 days of intense combat in Iran, part of Operation Epic Fury earlier this year, and subsequent retaliatory strikes. The US government reports the war has cost $37.5 billion (£28 billion) so far, with the majority allocated to munitions.

By the time a fragile ceasefire took effect on April 8, US forces had struck over 13,000 targets across Iran, according to the White House. Concurrently, American air defenses intercepted more than 1,700 Iranian drones and ballistic missiles.

The US has now paused its strikes on Iran to facilitate negotiations. A *New York Times* report indicates that Trump was advised against escalating the conflict further, as it would deplete American stockpiles.

On Monday, Trump refuted claims of a shortfall, telling the *Wall Street Journal*: "We have far more munitions than anyone in the world, and far more than we need."

Pete Hegseth has advocated for additional funding to replenish expended missiles. This has been a sensitive topic within the US administration for some time. Last month, when questioned, Hegseth denied that supplies were dwindling.

His stance appears to have shifted. Last week, he informed the Senate Appropriations Committee that the Pentagon required an additional $87 billion (£68 billion) to address "critical shortfalls," including equipment.

Precise ammunition expenditures and remaining stockpiles remain classified. Nevertheless, publicly available data compiled by the Washington D.C.-based Center for Strategic and International Studies (CSIS) reveals a stark picture of depleted stockpiles that are challenging to replace in the short term.

"It depends on the munition – but one to five years [to make a single missile] is the bottom line," states Mark Cancian, a retired Marine Corps colonel and senior adviser at CSIS who has researched the issue. "And there's nothing you can do to speed that up."

But is the US truly consuming ammunition so rapidly that it might struggle to fulfill its military obligations and objectives?

The critical munitions used in the war fall into two categories: long-range ground attack systems and the air and missile defenses employed to intercept incoming Iranian attacks.

Among the ground attack systems most heavily utilized was the Tomahawk Land Attack Missile (TLAM), typically launched from ships or submarines at targets potentially over 1,000 miles (1,609 km) away. These weapons enable the US to conduct precision strikes against hardened military targets, such as command bunkers or fortified military facilities, without endangering manned aircraft.

The CSIS estimates that over 1,000 Tomahawks have been fired during the war, and the stockpile may not return to pre-war levels until 2031. According to CSIS, the latest TLAM variants cost approximately $2.6 million (£2 million) per missile.

Of the air defense systems deployed, the Patriot, a ground-based missile designed to target aircraft, ballistic, and cruise missiles, saw the most extensive use. CSIS estimates that as many as 1,430 were used during the conflict from an estimated pre-war stockpile of about 2,330. Each Patriot interceptor costs approximately $4 million (£3.1 million) – an expensive yet effective option repeatedly used to shoot down Iranian drones, which themselves cost only between $20,000 and $50,000 each (£15,600–£39,000).

These will be difficult to replace. "It takes several years to produce a missile. If you put money into the system today, you wouldn't get a missile for three or four years. Sometimes even five," Cancian explains. "What we're getting [now] are missiles that were funded in 2023."

Also utilized was a newer, more sophisticated system known as Terminal High Altitude Area Defense (THAAD), which boasts a longer range and higher intercept altitudes than the older Patriot. Supplies were already limited, with CSIS estimating that between 190 and 290 were fired out of an estimated pre-war stock of 360. With only nine THAAD batteries operational globally – and seven of them American – sustained expenditure could leave US forces without a system crucial for defending against ballistic missile threats from nations such as Russia, China, or North Korea.

The war with Iran precedes what is often referred to as the "Davidson window," a period in which some US military planners believe a Chinese invasion of Taiwan becomes more probable.

This controversial concept, central to US military strategy in the Pacific, originated from a 2021 congressional hearing where Admiral Philip Davidson, then commander of US forces in the region, warned that an invasion would occur "in the next six years." In 2023, then-CIA director William Burns predicted China would be prepared to invade by 2027.

China has long vowed to "reunify" with self-governing Taiwan, which it considers a breakaway province, and has not ruled out the use of force.

Whether the US would defend Taiwan and engage in war with China is a hotly debated topic. Despite the ambiguity, the US provides the island with defensive weaponry.

The supply of missiles, including Tomahawks, has been depleted. Cancian refers to the munitions shortfalls as a "window of vulnerability" during which the US "is not going to have the depth of the preferred munitions it needs" if a conflict arises in the Pacific.

This, he believes, increases the risk of US forces being unprepared to confront a vast arsenal of Chinese missiles and aircraft that could be deployed in a Pacific conflict.

China, which US officials say has been closely observing US air defenses in the Iran war, has heavily invested in missile technology in recent years, including hypersonic glide missiles far more sophisticated than the missiles and inexpensive drones used by Iran. Beijing has also heavily invested in developing massive "drone-swarm" tactics.

However, not everyone views the depleted US stockpiles solely as a liability.

Jacob Olidort, a former CIA veteran and advisor on Middle East Policy in the Office of the Secretary of Defense, points out that using these weapons in combat also conveys a powerful message.

"Weapons create deterrence, not merely because nations have them, but also because they demonstrate a willingness to use them," said Olidort, now director for American security policy at the conservative-leaning America First Policy Institute.

He adds that US "successes at eroding Iran's military capabilities with precision, with record time, send a signal to other adversaries, including China and their ambitions."

The apparent tension between arming allies and preserving US reserves has already played out concerning Ukraine.

Back in October 2025, months before Operation Epic Fury commenced, Trump declined to provide Ukraine with Tomahawks, citing a need to avoid depleting US stockpiles.

This episode foreshadowed the trade-offs now shaping the post-Iran debate over the broader arsenal. Ukrainian officials urgently require Patriots and other air defense systems to counter waves of Russian drone and missile attacks.

"In addition to energy prices, it [the Iran war] means the depletion of US reserves, and the depletion of air defense manufacturers," Zelensky told the BBC in March. "So we [Ukraine] have a depletion of resources."

Ukraine has been petitioning for more Patriots to repel Russian attacks. Zelensky quantified the concern: the US produces approximately 60 to 65 missiles per month, or between 700 to 800 per year, with 803 used on the first day of Operation Epic Fury alone.

More recently, however, Trump surprised many European officials by offering Ukraine the right to domestically produce Patriots. Similar arrangements already exist in Germany and Japan.

Elaine McCusker, a 13-year veteran of the Department of Defense and now an expert with the American Enterprise Institute, suggests that Ukraine's experience fighting Russia – as well as the US experience fighting Iran – could help create cheaper, mass-produced systems to complement existing high-cost items.

"We've known for a long time that we don't want to be shooting $6 million interceptors at $1,000 drones," she says. "I think we now have more focus on that solution, and more people focusing on manufacturing more attritable solutions that don't cost so much."

Despite these concerns, there is little immediate alarm about munitions running out if the war reignites – not because US stockpiles are unlimited, but because Iran's are in a far worse state.

"The United States military has more than enough munitions, ammo, and stockpiles to serve all of President Trump's strategic goals and beyond, and Operation Epic Fury has exposed what happens when you mess with the United States," White House spokesperson Anna Kelly said in a statement sent to the BBC.

"Even still, the president has urged our defense contractors to constantly produce more made-in-America weapons," she added.

Recent strikes announced by US Central Command have primarily focused on degrading Tehran's ability to threaten ships in the Strait of Hormuz, the vital shipping lane that Iran and the US have blockaded.

Iran's stockpiles have also been depleted. Iran's military losses have significantly surpassed America's following successive waves of US and Israeli strikes, and the country has extremely limited capacity to address these shortages anytime soon.

"A lot of commentary portrays Iran as having an almost unlimited amount of weaponry," says Jason Brodsky, policy director of United Against Nuclear Iran.

"I think we have to realize that there are limitations there, and that the US has degraded their defense industrial base to a very significant extent," he says.

He adds that Iran's "capacity to produce, at scale, the kinds of missiles, drones and other weapons systems" it needs has been largely destroyed.

Iran's remaining stockpiles, according to Brodsky, are being funneled towards what he termed Tehran's trump card – its ability to threaten the Strait of Hormuz. In his view, it is a fading capability. "The Iranian regime is running out of time here."

The current, manageable conflict with Iran – what Brodsky called the US military's "center of gravity" – takes immediate precedence for Washington, even as officials acknowledge it would be "irresponsible" to ignore the broader stockpile situation.

"The Indo-Pacific is a more distant threat right now," he says. "Policymakers have to prioritize, and the Middle East right now has the president's attention."

For now, every missile fired at an Iranian target, sent to Ukraine's frontlines, or held back for Taiwan, comes from a steadily shrinking pool. Despite this, Washington is betting it can navigate this conflict while production catches up.