The United States’ growing munitions deficit is not merely the consequence of the ongoing conflict with Iran; rather, it reflects a deeper structural imbalance between America’s strategic ambitions and the capacity of its defence industrial base. Decades of post-Cold War assumptions, that major interstate wars were unlikely, encouraged successive administrations to prioritise efficiency over surge capacity. The result has been an industrial ecosystem optimised for peacetime procurement rather than sustained, high-intensity warfare. The wars in Ukraine and the Middle East have exposed the limits of this model.
The immediate causes of the shortage are clear. Sustained military assistance to Ukraine, including millions of 155 mm artillery rounds, Patriot interceptors, Javelin anti-tank missiles, and Guided Multiple Launch Rocket Systems (GMLRS), had already reduced US inventories. Continued support for Israel, prolonged operations against the Houthis in the Red Sea, and, most recently, the 2026 military campaign against Iran have further accelerated the depletion of critical stockpiles. Reports suggest that the Iran campaign consumed a significant proportion of advanced precision munitions, including Tomahawk cruise missiles, Precision Strike Missiles (PrSM), Patriot and THAAD interceptors, and naval air-defence missiles such as the SM-3 and SM-6. Consumption rates have significantly exceeded peacetime production levels, exposing the mismatch between operational requirements and industrial output.
The roots of this problem, however, lie in the gradual erosion of the American defence industrial base. Following the Cold War, consolidation within the defence sector reduced the number of suppliers, while production lines for critical inputs, including solid rocket motors, explosives, shell bodies, rare-earth components, and microelectronics, were either scaled back or allowed to stagnate. The emphasis on lean supply chains and cost efficiency created multiple single-source bottlenecks, leaving the United States with limited capacity to rapidly expand production during crises. Equally significant has been the decline in skilled manufacturing labour and ageing production infrastructure, both of which constrain the speed with which industrial output can be increased.
Efforts to reverse this trend have produced only modest results. Despite substantial investments to expand artillery shell production, output has grown far more slowly than planned, with persistent shortages of explosives, metal components, and qualified manufacturing capacity limiting progress. Similar challenges affect the production of high-end missile systems. Weapons such as Patriot interceptors, THAAD missiles, and Tomahawk cruise missiles require long production cycles, highly specialised supply chains, and industrial investments that cannot be created overnight. Financial allocations alone cannot rapidly generate the workforce, facilities, and supplier networks necessary for sustained expansion.
Policy choices have compounded these structural constraints. Procurement patterns characterised by fluctuating orders, prolonged acquisition timelines, and an emphasis on sophisticated platforms rather than stockpile depth discouraged industry from investing in excess capacity. Globalised supply chains and inadequate pre-crisis planning further reduced resilience. Although recent initiatives, including expanded defence funding, the use of the Defense Production Act, and long-term industrial agreements, represent important corrective measures, they are unlikely to produce meaningful increases in output in the immediate future.
Operationally, the United States has retained sufficient inventories to sustain military operations against Iran under the current scope of the conflict. Conventional air-delivered munitions, including JDAMs, Small Diameter Bombs, and Hellfire missiles, remain available in substantial numbers. Nevertheless, the extensive use of high-end stand-off weapons and missile-defence interceptors has narrowed Washington’s strategic flexibility. Decisions regarding escalation have increasingly been shaped not only by political considerations but also by concerns over inventory management. The strain on stockpiles has also complicated continued military assistance to partners and affected the readiness of naval and air assets deployed across multiple theatres.
The broader strategic implications extend well beyond the Middle East. American war games have repeatedly demonstrated that a high-intensity conflict in the Indo-Pacific, particularly over Taiwan, would consume precision-guided munitions at a pace far exceeding current production capacity. The depletion of inventories during the Iran campaign thus widens an already recognised capability gap. While it does not fundamentally undermine US deterrence against China, it reinforces concerns regarding America’s ability to sustain simultaneous operations across multiple theatres and prolonged conventional conflicts against peer competitors.
Ultimately, the current munitions shortage illustrates the disconnect between contemporary patterns of warfare and the assumptions that shaped American defence planning after the Cold War. The United States retains overwhelming military capabilities and sufficient resources to prosecute the Iran campaign as presently envisaged. However, rebuilding inventories and restoring adequate wartime reserves will require sustained procurement, significant expansion of industrial capacity, and greater resilience across critical supply chains. These are long-term structural challenges whose resolution will be measured in years rather than months.
(Harsh V Pant is Vice President for Studies at Observer Research Foundation, New Delhi.)
Disclaimer: These are the personal opinions of the author
