The US Is Running Low on Ammo—That's Not Even Trump's Top Iran War Problem

A "surprise" Iranian missile salvo targeting U.S. bases in the Middle East amid a new White House pivot to diplomacy marks the latest test for the United States' dwindling munitions stockpiles.

"The United States has burned through Patriot, THAAD missile interceptors, and long-range strike missiles at an extraordinary rate," Kelly Grieco, senior fellow with the Stimson Center's Reimagining U.S. Grand Strategy Program, told Newsweek. "In the near term, this is a force-protection issue."

Both U.S. systems are sophisticated and costly to sustain in active combat. The latest PAC-3 MSE Patriot interceptors run roughly $4 million per unit, while THAAD (Terminal High Altitude Area Defense) interceptors run on average at closer to $12 million each.

In their assessment, experts at the Center for Strategic and International Studies (CSIS) estimated that the U.S. has used up between one-third and one-half of its reserves of seven key munitions, including Patriot and THAAD interceptors, SM-3 and SM-6 ship-based surface-to-air missiles, land-launched Precision Strike Missiles (PrSMs), air-launched Joint Air-to-Surface Standoff Missiles (JASSMs) and Tomahawk cruise missiles.

The research found Patriot interceptors down to around 1,000 from a pre-war estimate of 2,500, while THAAD interceptors have dwindled to around just 70–170 from an estimated count of 360 prior to the war launched by the U.S. and Israel against Iran in February.

CSIS Defense and Security Department senior adviser Mark Cancian, who previously served as chief of the Force Structure and Investment Division at the White House's Office of Management and Budget, argued the issue was not immediate in the Middle East, as "there's enough left for continuing the war against Iran for an extended period."

"The risk is in a future war particularly against China but also against North Korea or Russia," Cancian told Newsweek. "Even before the current war, most analysts considered the inventories to be insufficient for a war against China and they are now even lower."

"It will take one to five years to get the inventories back to where they were pre-war and another several years after that to get to where war planners want them to be," Cancian said. "That creates a window of vulnerability."

The Department of Defense, for its part, remains confident in U.S. capabilities.

"America's military is the most powerful in the world and has everything it needs to execute at the time and place of the President's choosing," chief Pentagon spokesman Sean Parnell said in a statement shared with Newsweek.