The United States would deplete its Terminal High Altitude Area Defense interceptors by April 17, 2026, if the pace of fighting with Iran continues. The U.S. Army Tactical Missile System and Precision Strike Missile munitions stockpiles would run out by April 12, 2026, at the current combat tempo.

The U.S. and its allies expended 11,294 munitions in the first 16 days of the conflict. Roughly 5,000 munitions were fired in the first four days alone. After damage to radars and satellite terminals, intercepting a single missile can require 10 or 11 interceptors and intercepting a single drone can require eight Patriot missiles.

Gen. Dan Caine, Chairman of the Joint Chiefs of Staff, said ballistic missile launches by Iran dropped by 86% after the war's first four days. Caine said drone attacks by Iran dropped by 73% during the same period. Following this initial drop, a daily average of 33 Iranian missile attacks and 94 drone strikes occurred.

The Terminal High Altitude Area Defense missile defense system can intercept long-range ballistic missiles and other threats inside Earth's atmosphere. Two to three U.S.-operated THAAD batteries are deployed in the Middle East, with five THAAD batteries deployed outside the continental United States. THAAD interceptors can cost up to $15 million each.

The Army Tactical Missile System and the Precision Strike Missile are ground-launched missiles capable of striking targets more than 180 miles away. The Precision Strike Missile made its combat debut during the Iran war. Defense Department records show that the U.S. manufactured at least 328 Precision Strike Missiles in the last two years and plans to produce another 124 this year.

The U.S. fired more than 500 Tomahawk missiles against Iran during the conflict, and it would take at least five years to replace them. Replenishing expended munitions at speed would likely cost around $50 billion. Restocking approximately 500,000 20mm rounds fired from air defense systems during the conflict requires about 8,800 pounds of tungsten, and China controls over 80% of the global supply of tungsten.

U.S. stockpiles of advanced air defense interceptors and ground-attack missiles have long been a concern because depleting them could undermine the Pentagon's ability to maintain deterrence in theaters such as the Indo-Pacific. Researchers recommended investing heavily in the defense industrial base and building a layered air defense system combining cheaper and more advanced defenses.