The United States fired more than 1,000 Tomahawk cruise missiles and hundreds of Patriot and Terminal High Altitude Area Defense interceptors during military operations against Iran, and a new analysis from the Center for Strategic and International Studies projects it will take years to rebuild those stockpiles. The Washington-based think tank said Wednesday that the depleted inventories leave American forces with reduced firepower in any future conflict in the Western Pacific — a region where China has signaled it may attempt to take Taiwan by force.
“The United States has enough munitions for any plausible scenario in the Iran war, but the depleted inventories have created a window of vulnerability for a potential Western Pacific conflict,” CSIS said in its report, which was provided to The Associated Press. “The time needed to rebuild those inventories has thus become a major concern.”
The analysis examines three weapons systems central to the Iran campaign. Tomahawk cruise missiles — used to strike targets deep inside enemy territory — were fired at a rate that exhausted the prewar inventory. CSIS estimates that at current production rates of fewer than 200 missiles per year, full replenishment could stretch into late 2030. Raytheon, the manufacturer, has set a goal of raising capacity to more than 1,000 annually. RTX, Raytheon’s parent company, declined to comment on the CSIS findings because it had not yet seen the report, but pointed to investments of several billion dollars to expand facilities in Alabama and Arizona.
For air defense, the U.S. expended roughly 290 THAAD interceptors and more than 1,000 Patriot interceptors shooting down incoming Iranian drones and missiles. CSIS estimates that replacing the THAAD rounds could take until the end of 2029, while Patriot replenishment should wrap up in mid-2029. Lockheed Martin, which produces both systems, said in a statement that it is investing $9 billion through 2030 and “is already delivering tangible results to meet heightened munitions demand,” including a new facility in Alabama announced last week.
“Patriot deliveries pose a dilemma for the United States because of the need to replenish its own inventories, help Ukraine defend against Russian missile attacks, and meet the needs of 17 other countries that use the interceptor,” the report said.
The analysis factors in the Trump administration’s proposed $1.5 trillion defense budget for 2027, which significantly accelerates prior spending on high-end munitions. Chief Pentagon spokesman Sean Parnell said in a statement that the military “has everything it needs to execute at the time and place of the President’s choosing,” adding that the U.S. has “executed multiple successful operations across combatant commands while ensuring the U.S. military possesses a deep arsenal of capabilities.”
President Donald Trump and Defense Secretary Pete Hegseth have pushed defense contractors to speed up production, with Hegseth telling lawmakers last month that military spending under Trump will help manufacturers double or even triple capacity. At a Cabinet meeting Wednesday, Hegseth lauded the president’s efforts to expand the defense manufacturing sector.
Some military experts have pushed back against the administration’s assurances. Virginia Burger, a senior defense policy analyst at the Project On Government Oversight and a former Marine officer, said Pentagon officials “knew the reality of our military stockpiles and hopefully told someone, ‘Hey, if we go to this fight, even in the most conservative estimates, we are drawing down our stockpiles to a critical level.’”
The munitions supply has become a flashpoint in congressional hearings. Democrats have cited the depleted inventories as evidence that the Iran war — launched without lawmakers’ approval — was strategically costly. Some Republicans argue the problem originated with the Biden administration’s decision to send Patriot systems to Ukraine after Russia’s 2022 invasion.
Mark Cancian, a retired Marine colonel and senior adviser at CSIS who co-authored the study with research associate Chris H. Park, traced the roots of the predicament to the end of the Cold War. After the fall of the Soviet Union in 1991, Cancian said, the U.S. assumed future wars would be short and regional, requiring few high-end weapons. The Pentagon ordered relatively low numbers, and contractors maintained a small manufacturing footprint. Russia’s war with Ukraine changed that calculus, showing that protracted conflicts demand deep inventories.
“The thinking started to change, but it just takes time to build inventories,” Cancian said, noting the challenge of reviving a complex web of supply chains and subcontractors that produce novel components. He credited the Biden administration for beginning conversations with the defense industry and ramping up production. “A lot of people in the Trump administration are inclined to say that everything was terrible until they arrived, and that’s not true,” he said. “Now, it is true that the Trump administration really increased funding.”
Despite the vulnerability window, CSIS said the outlook for deterrence against China is “not all bleak.” The U.S. military recently demonstrated its capabilities in combat operations against Iran, Venezuela and Houthi rebels in Yemen. “China is deeply aware that it has no recent combat experience and that it performed poorly in its last war — against Vietnam in 1979,” the report said. “That difference in experience may preserve deterrence until munitions inventories are restored.”