Many of these systems are constrained by production capacity, so manufacturing lead time is even longer. On the bright side, previous funding going back to the Biden administration supported the expansion of production rates for many systems, so the cycle time will come down.
Low-Cost Alternatives
The high-cost/low-inventory dynamics described above have driven many experts in and out of government to recommend that the United States build low-cost systems to complement or even replace the high-cost systems. Indeed, the FY 2026 reconciliation bill contains several billion dollars for this purpose (Sections 20004 and 20005).
As Figure 1 shows, the United States already has many inexpensive and short-range systems for ground attack. First-person view drones—which are vital to fighting in Ukraine—are not useful here because of their limited range of roughly 20 miles. To field an inexpensive and long-range system, the United States copied the Iranian Shaheed-136 (as did Russia). The result was the Low-Cost Uncrewed Combat Attack System (LUCAS).
The LUCAS ( $35,000) provides an affordable way to deliver standoff precision attacks, with a range of roughly 500 miles. The tradeoff is that it carries a small warhead of 40 pounds. The United States used some in the Iran war but did not have enough to match the salvos launched by Iran in this war or by Russia in Ukraine.
The other category is counter–unmanned aerial systems (c-UASs). The Department of Defense (DOD) began work on the c-UAS about a decade ago, but that proceeded at a measured pace. The war in Ukraine demonstrated how important such systems were, so the United States sent some prototype systems to support Ukraine and accelerated its own efforts. These efforts have produced several low-cost ways to intercept the inexpensive Iranian drones:
- Advanced Precision Kill Weapon System (APKWS): This is a helicopter-launched Hydra 70 rocket with a laser seeker.
- Roadrunner and Coyote: These are low-cost interceptor drones developed by Anduril and Raytheon, respectively. They intercept and destroy oncoming drones by crashing into them.
- Counter Rocket, Artillery, and Mortar System (C-RAM): This is a radar-controlled rapid-fire gun for close-in protection, based on the Navy’s Phalanx system. Although excellent for protecting specific locations against drones, its use in populated areas is limited because of collateral damage from descending projectiles.
Except in rare cases, the United States has not used the very expensive systems (Patriot or SM-6) against cheap drones (the Gulf states may have done that in the early days of the conflict). It also has not had enough cheap interceptors. As a result, the United States and the Gulf states have used helicopters with guns, fixed-wing aircraft with guns, and air-to-air missiles to conduct the intercepts. Some of these air-to-air missiles (AIM-120) cost $1 million each. It is better to use one of those than let the drone get through, but that is not a long-term solution.
A Methodological Primer on Missile Calculations
This section describes how CSIS developed the numbers in this analysis.
Munition inventories are classified, but publicly available information is sufficient to make estimates. The annual DOD budget documents are the starting point to calculate the total number of missiles delivered to the U.S. military:
- Exhibit P-5 provides the number procured and unit cost of missiles by each variant. Assuming a 20-year shelf life, older variants are included in the estimates, provided they were delivered during or after FY 2005. The estimated Patriot interceptor inventory, for example, includes around a thousand PAC-3 missiles—alongside the MSE variant. Excluded are munitions procured for Foreign Military Sales or research and development.
- Exhibit P-21 shows the delivery timeline and quantity. Inventory estimates in this commentary include missiles that the DOD projected for delivery by February 2026 when it released the FY 2026 budget documents in June 2025.
Of the total deliveries, 5 percent was deducted for training, lot testing, and other nonoperational uses. Reported and estimated expenditures in past campaigns were also subtracted, where applicable. Deliveries to Ukraine from U.S. stockpiles came from DOD releases and our previous estimates.
Estimated munitions use during Operation Epic Fury was derived from the approach used in CSIS’s cost estimate of the war, detailed in a previous commentary. The starting point here was, again, DOD-released numbers that were then combined with data from Gulf countries, the theater order of battle, and historical employment patterns. The high and low estimates take into account that the actual expenditures will be highly sensitive to the coalition’s contributions to air defense, share of long-range systems for strikes, and the mix of munitions used. For TLAM and JASSM, the analysis reflects expenditures reportedly shared by DOD officials.
The best source on the various munition programs is the Selected Acquisition Report, where available, because of its comprehensive acquisition data. The FY 2027 budget amounts came from the DOD-published materials in early April. Though these documents are incomplete, they provide the number of munitions to be funded. Unit cost of missiles can vary year-to-year. This analysis provides the latest figures based on the FY 2026 budget documents.
Conclusion: Risk in the Next War
If inventories are so depleted, how can the analysis conclude that the United States has enough munitions for this war? The answer lies in the dramatic drop in usage from the early days of the war. For ground attacks, the less expensive and more plentiful munitions of Figure 1 have largely replaced the long-range munitions (TLAMs, JASSMs, and PrSMs). Air and missile defense expenditures came down because Iran’s drone and missile attacks were way down after the first few days. Whereas Iran fired more than 2,000 drones and 500 ballistic missiles in the first four days, launches were down, respectively, by 83 and 90 percent after a week.
The diminished munitions stockpiles have created a near-term risk. A war against a capable peer competitor like China will consume munitions at greater rates than in this war. Prewar inventories were already insufficient; the levels today will constrain U.S. operations should a future conflict arise.
President Trump has accepted this munitions risk—alongside other tradeoffs like the diversion of forces from the Western Pacific. The theory here appears to be that it is important to decisively win the current war you are in, rather than to hold back and preserve capability for a future war that may never happen. Once Operation Epic Fury ends, the naval assets sent to the Middle East will return to the Pacific. Munitions inventories will start to recover, but restoring depleted stockpiles and then achieving the desired inventory levels will take many years.
Mark F. Cancian (Colonel, U.S. Marine Corps Reserve, ret.) is a senior adviser with the Defense and Security Department at the Center for Strategic and International Studies (CSIS) in Washington, D.C. Chris H. Park is a research associate for the Arleigh A. Burke Chair in Strategy at CSIS.
Madison Bruno and Sabina Hung reviewed and formatted this report with their characteristic—and sincerely appreciated—alacrity and diligence.
If you are interested in learning more about this topic, explore CSIS’s Executive Education courses Meeting China’s Military Challenge and Inside DOD’s FY 2027 Budget.
