Iran War & Hormuz — 2026-04-22

CSIS: US expended ~45% of Patriot and 50% of THAAD interceptors during seven-week Iran campaign, five-year replenishment timeline

A CSIS assessment reported by CNN on April 21 and widely corroborated on April 22 calculates that US forces expended at least 45 percent of Precision Strike Missile inventory, approximately 50 percent of Patriot and THAAD interceptors, roughly 30 percent of Tomahawk land-attack missiles, more than 20 percent of JASSM stocks, and approximately 20 percent of SM-3 and SM-6 missiles during Operation Epic Fury. CSIS analyst Mark Cancian told CNN that replenishment would require four to five years at current production lines. Rep. Pat Ryan (D-NY, House Armed Services) cited the figures on the House floor, saying stockpiles were insufficient for a peer-competitor fight before the campaign began. Multiple outlets noted the implications for Western Pacific contingencies where Patriot and THAAD are central to theater missile defense.

Analysis
Per a single CSIS assessment (Mark Cancian on-record, corroborated April 22, historically within ±5 percent of leaked Pentagon figures), Operation Epic Fury very likely constrains US theater-missile defense and long-range strike options in the Western Pacific through at least 2028, a capability shock without precedent since the 1980s Ready Reserve drawdown. A four-to-five-year replenishment timeline holds only if Raytheon and Lockheed production lines remain intact, themselves contingent on rare-earth magnet and solid-rocket-motor supply chains already flagged as fragile. Taiwan-contingency planners must now operate against FY25 war-game assumptions built on a Patriot and THAAD cupboard that no longer exists. Within the coming months, Pacific Command will likely formalize revised allocation priorities that disadvantage Ukraine's Patriot pipeline and Saudi/UAE missile-defense commitments. Rep. Pat Ryan's House floor citation of the CSIS figures converts them from contested journalism into load-bearing congressional material, with FY27 supplemental debates over Golden Dome and Patriot co-production emergency funding likely to resolve within the next 30–60 days. The vulnerability window may run longer than five years if classified PAC-3 MSE and SM-6 expenditure exceeded open-source attribution, meaning the CSIS figures understate the actual drawdown.

3 sources