The U.S. is Facing an Ammunition Shortage Due to the Iran War. Here’s What That Means

(SeaPRwire) –   Last week, Sen. Mark Kelly, a retired Navy Captain and former astronaut, drew the Pentagon’s anger after voicing alarm over U.S. weapons stockpiles diminished by the Iran War. 

Referring to a Department of Defense (DOD) briefing, Kelly informed CBS’s “Face the Nation” host Margaret Brennan that replenishing stocks of Tomahawks, Patriots, and other long-range munitions deployed in the U.S. and Israeli assault on Iran could require “years”—a situation that might expose the U.S. to global vulnerabilities. 

These statements led Defense Secretary Pete Hegseth to initiate a probe into Sen. Kelly’s comments, charging him with disclosing classified data.   

However, Mark Cancian, a senior adviser at the Center for Strategic and International Studies (CSIS) Defense and Security, states that Kelly is correct regarding these weapon shortfalls.

“The DOD actually has more funds than it can expend on munitions. The issue is time,” he remarks. “Production will ramp up, but that requires three to four years before supply catches up with demand,” he informs TIME. 

Furthermore, the issue will create consequences extending well past the U.S., impacting global allies who have arms agreements with Washington.

“Gulf States seek to restore their air and missile defense stocks. Ukrainians require Patriots. Japan desires Tomahawks, and other nations may also wish to enlarge their inventories,” Cancian notes. “For the next few years, there simply will not be sufficient missiles available.”

The following explains what ammunition deficits could signify for the U.S. and its global partners.

Fears over readiness for war with China

In May 2025, Hegseth identified China as an “imminent” danger to Taiwan. The Trump Administration urged Asian allies to adopt a firmer position against Beijing, and in recent years, multiple senior officials have forecast that China might attempt to invade Taiwan as soon as 2027, potentially pulling the U.S. into a clash with the military giant.

The Iran War has exhausted U.S. munitions reserves to a degree that rebuilding them will demand “one to four years, based on the weapon,” according to Cancian—provided the U.S. avoids additional conflicts.

“Subsequently, it will require several more years to bring stockpiles to the levels desired for a confrontation with China.”

Cancian contends that supplies of some munitions are adequate—”we’re not going to be reduced to throwing rocks at them,” he states—but the missiles most valuable in a potential clash with China over Taiwan would be scarce. 

This outcome could lead to higher U.S. military casualties if war occurs.

“We would need to employ short or medium range munitions in place of long range ones, meaning you must approach much closer. That renders the platforms far more exposed,” Cancian explains.

Fewer weapons for Ukraine

Even before the Iran War, Ukraine was already experiencing a deficit of U.S.-manufactured Patriot air defense missiles, which are particularly potent against Russian ballistic missiles.
However, as U.S. troops and American partners in the Gulf utilized these Patriot systems to counter waves of Iranian drones and missiles, Ukraine now confronts a severe shortage.

Earlier this month, the Financial Times disclosed that recent Pentagon announcements of weapon delays to Europe will also impact High Mobility Artillery Rocket System (HIMARS) ammunition, a highly mobile rocket platform employed by Ukraine.

Still engaged in conflict with Russia, Ukraine is now striving to develop its own missile defense network. In early May, President Volodymyr Zelensky told fellow European leaders that the continent “must be capable of manufacturing all it requires to counter every threat—all ballistic assaults and all other weapons—independently.”

Limits of production 

Despite the Trump Administration designating an extra $150 billion for the Department of Defense (DoD) in the One Big Beautiful Bill enacted last year, Cancian asserts that funding is not the primary obstacle.

Production capabilities limit many of the relevant weapons systems. 

Constructing and delivering a Tomahawk, for instance, requires 47 months, and 48 months for a JASSM (Joint Air-to-Surface Standoff Missile), a long-range cruise missile produced by Lockheed Martin. 

These supply challenges originate from 2022, when the war in Ukraine imposed comparable pressures on inventories during the Biden Administration. 

Certain analysts view the U.S. military-industrial base as antiquated, dependent on World War II-era production frameworks. Although manufacturing methods are undergoing modernization, some proponents recommend the government seek inexpensive substitutes for premium weapons systems. 

The necessity for affordable alternatives to systems like Patriot missiles became clear during Iran’s onslaught of low-cost drones targeting the Gulf.

“[T]he United States and the Gulf states have employed helicopters with guns, fixed-wing aircraft with guns, and air-to-air missiles to perform the interceptions. Some of these air-to-air missiles (AIM-120) are priced at $1 million apiece. Using one is preferable to allowing a drone to penetrate, but that does not constitute a sustainable fix,” Cancian wrote in a CSIS report released in late April.