U.S. Munitions Stockpiles a Concern Amid Rising Iran Tensions
Limited supplies of critical defensive munitions to protect U.S. Forces and allies from Iranian missiles are emerging as a key factor shaping potential American military options, according to officials, and analysts. The U.S. And Israel significantly depleted their interceptor stockpiles during the 12-day conflict in June 2025, when Iran launched hundreds of missiles at Israel. Replenishing these supplies is proving challenging, potentially impacting not only support for Ukraine but similarly contingency plans for conflicts with China or Russia.
Depleted Stockpiles and Magazine Depth
The “magazine depth”—military terminology for available munitions—of the U.S.’s Terminal High-Altitude Area Defense (THAAD) anti-missile systems is a particular concern. Approximately 150 THAAD munitions were reportedly fired in defense of Israel last year, despite the U.S. Having ordered fewer than 650 since the system’s introduction around 2010.
Stacie Pettyjohn, director of the defense program at the Center for a New American Security, suggests the U.S. Could “easily” expend a “whole year’s worth” of critical defensive munitions in just one or two days if Iran were to launch multiple large-scale missile and drone attacks against U.S. Forces and Israel. Center for Preventive Action
Strategic Considerations and Potential Limitations
While officials believe Iranian missiles are unlikely to exhaust U.S. Defensive munitions entirely, preserving those munitions for other theaters could necessitate Israel taking greater responsibility for its own defense while the U.S. Protects its forces and allies.
In April 2024, U.S., French, and British forces assisted in defending Israel against hundreds of Iranian drones, cruise, and ballistic missiles launched in retaliation for the assassination of Iranian officials. Though, no similar international coalition is currently in place for Israel’s defense.
Iran and its regional proxies have employed a “saturation method,” overwhelming enemy aerial defenses with massive barrages of cheaper missiles. This strategy is a key consideration in U.S. Planning for any potential offensive.
Munitions Usage and Production Challenges
During the 2025 conflict, the U.S. Navy fired at least 80 sophisticated seaborne missiles, including the SM-3, which saw its first combat use protecting Israel. Procurement of the SM-3 is limited to 12 missiles this fiscal year at a cost of $445 million. The Pentagon plans to spend $840 million on 37 THAAD interceptors in fiscal year 2026 and requested $1.3 billion for 96 Patriot missiles this fiscal year.
Admiral James Kilby noted in June 2025 that the Navy had depleted its interceptor missiles at an “alarming rate” during the 12-day war. CBS News By January 2025, the Navy had also used approximately 200 SM-2 and SM-6 missiles during its campaign against Houthi militants in the Red Sea. Naval destroyers require return to port for missile reloading, limiting sustained operations near Iran.
Doug Birkey, executive director of the Mitchell Institute for Aerospace Studies, emphasized that any “air campaign right now is going to be fundamentally governed by our magazine depth,” which has “been taxed significantly supporting a variety of operations around the world.”
Offensive Munitions and Production Boosts
Analysts suggest the U.S. Would likely employ Tomahawk missiles in any conflict with Iran to avoid exposing non-stealthy fighter jets to Iranian airspace. Tomahawks were used in previous engagements against Houthi rebels and in the 2025 bombing of Iranian facilities and would also be crucial in potential conflicts with Russia or China.
Production issues stem from inconsistent demand signals from the Pentagon. Without long-term contracts, defense companies lacked incentives to increase production. The U.S. Is now attempting to “turbocharge” production through agreements with major manufacturers.
Potential for Restrained Response
While a muted Iranian response, similar to the June 2025 assault on a U.S. Airbase in Qatar following U.S. Strikes on Iranian nuclear facilities, is possible, it is not guaranteed. Vice Admiral Charles Cooper highlighted the “judicious use” of missiles as crucial for conserving magazine depth, noting a shift towards using less expensive options against drones.