U.S. Missile Defense Stocks Drained by War with Iran, Leaving Vulnerability to China

The United States' missile defense capabilities are facing a critical shortage following extensive use of interceptors in its ongoing conflict with Iran, according to a recent Congressional Budget Office (CBO) report. The report highlights that the U.S. has likely expended between one-half and two-thirds of its existing missile defense interceptors during operations against Iran. This depletion raises significant concerns about America's ability to defend itself or its allies should a confrontation arise with China.

The CBO report, released on Tuesday in response to a request from Representative Brendan F. Boyle (D-Pa.), details the substantial expenditure of costly and essential missile defense systems such as Patriot and Terminal High Altitude Area Defense (THAAD) interceptors. These systems are crucial for countering ballistic and cruise missiles, which pose a significant threat during conflicts like those potentially involving Taiwan.

The report underscores that replenishing these expended resources will take considerable time and financial investment. It is projected to take at least five years to replace the used interceptors due to their high cost and complex production processes. This timeline exacerbates concerns about U.S. readiness in the face of a potential conflict with China, whose military arsenal includes large numbers of ballistic and cruise missiles.

The Department of Defense has been increasingly focusing on missile defense as its primary deterrent against Chinese aggression in the Indo-Pacific region. However, recent shifts in strategic priorities have seen some missile defense systems redeployed from South Korea to support operations in the Middle East. This reallocation further strains U.S. defensive capabilities in key regions.

Specifically, the report notes that a significant portion of missile interceptors were utilized to defend Israeli assets against Iranian ballistic missiles in June 2025, with nearly 150 THAAD interceptors and 80 Standard Missile-3s deployed during these operations. The Pentagon's Operation Epic Fury, which concluded combat operations against Iran in May, has further reduced the inventory of available missile defense systems.

The implications of this report are profound for U.S. security strategies moving forward. With a diminished stockpile of interceptors and an extended period required to replenish them, policymakers must carefully weigh the risks and potential reallocations of military resources. The ongoing conflict with Iran not only impacts regional stability but also has far-reaching consequences for global defense postures, particularly in relation to China's expanding military capabilities.

In light of these findings, there is growing urgency among U.S. officials to reassess and possibly adjust current defense strategies to ensure adequate preparedness against multiple threats simultaneously. This includes considering innovative solutions such as technological advancements or international collaborations aimed at bolstering missile defense systems more efficiently.