The United States has expended approximately two-thirds of its critical Patriot missile interceptors since the onset of the war with Iran, according to a new report from the Center for Strategic and International Studies (CSIS). The ongoing exchange of drone and missile strikes in the region is further depleting these vital defense resources.
Prior to the conflict, the U.S. maintained a stockpile of over 2,700 missiles for both the Patriot and the anti-ballistic THAAD systems. As of Monday, this supply has decreased to fewer than 1,000 missiles, with only 827 Patriot missiles remaining. These Patriot batteries have served as the primary defense against Iranian drones and missiles launched across the Middle East.
While the U.S. has achieved a high interception rate, several Iranian attacks have recently breached defenses. The CSIS report warns that a continued reduction in defense stockpiles could increase the risk to U.S. soldiers and military bases. Mark Cancian, a retired Marine colonel and senior adviser at CSIS, noted that even small increases in usage contribute to the overall depletion.
During the initial six days of "Operation Epic Fury," American forces expended a significant number of missiles to dismantle Iranian launchers, aiming to prevent overwhelming retaliatory attacks on already reduced U.S. air defense systems, which were also supplying interceptors to Ukraine. Although Iran's attack frequency has decreased since the war's outset, the country continues to launch daily, increasingly sophisticated strikes.
Earlier this month, at least three missiles bypassed U.S. defenses at the Muwaffaq Salti Air Base in Jordan, resulting in the deaths of three U.S. soldiers. The available Patriot interceptors saw a drop from 1,030 at the start of an April ceasefire to between 759 and 827, representing an overall decrease of at least 65% since the conflict began. Each PAC-3 MSE Patriot interceptor costs approximately $3.9 million and takes up to two years to manufacture.
The THAAD interceptor stockpile, designed to counter advanced ballistic missiles up to 125 miles away, also diminished. Missile counts fell from 452 before the war to between 232 and 262 at the start of the April ceasefire. Although the U.S. has replenished the THAAD stockpile with about a dozen missiles, the total remains 38% smaller than pre-war levels.
The CSIS report highlights a significant challenge: "no good alternatives to Patriot and THAAD for ballistic missile defense." The Pentagon has asserted that sufficient weapons are on hand and that procurement is ongoing, pushing back against concerns over depleted stockpiles. Analysts indicate that while the U.S. possesses enough munitions, particularly attack weapons, to sustain the current conflict, the reduced defensive supply could alter U.S. responses to future attacks on its Middle East bases, potentially leading to acceptance of minor damage to infrastructure or areas without personnel.
The diminishing missile defenses have also sparked concerns about the U.S. readiness for a potential conflict with China in the western Pacific.