The United States possesses sufficient munitions for any foreseeable scenario in the ongoing war with Iran, but replenishing its depleted stockpiles will require several years, according to a new report from the Center for Strategic and International Studies (CSIS).

Restoring pre-war levels of four critical munitions heavily utilized during the nearly 40 days of joint U.S. and Israeli combat against Iran will take a minimum of two years, and potentially over three years in some instances, the Washington-based think tank stated.

While U.S. officials maintain confidence in their current weapons reserves, analysts suggest that the diminishing supply of munitions may be influencing Washington's decisions regarding a potential resumption of hostilities against Iran. The CSIS report noted that "campaigns against Iran and its proxies – and, for Patriot interceptors, aid to Ukraine – have made the problem more acute."

Beyond refilling its own inventories, the United States must also fulfill orders from allied nations and partners, adding further strain to production capacities. The report highlighted that the four key munitions depleted by more than half their pre-war levels include the Land Attack Missile (TLAM), Terminal High Altitude Area Defences (THAAD) interceptors, Patriot missiles, and the SM-3 and SM-6 ship-based surface-to-air missiles.

Munitions like the Joint Air-to-Surface Standoff Missile (JASSM) and Precision Strike Missile (PrSM) are projected to take several months to a year to replace. The report attributes the low pre-war inventory of PrSM to its recent entry into production, while JASSM, despite heavy use in the Iran war, is expected to see significant deliveries from recent procurement orders.

The primary challenge is not a lack of funding, but rather the constraints of production time, limited manufacturing capacity, and lengthy procurement lead times. CSIS pointed out that historical procurement levels for many systems were relatively low, which has slowed replacement efforts even with recent increases in defense spending.

"There will be a window of vulnerability for several years until inventories return to their previous levels and another several years before they get to the levels that war planners desire," the report warned. This situation could create friction between nations as new production is allocated, a dynamic expected to persist as demand continues to outpace supply.

The CSIS analysis suggests that the depleted munitions stockpile could represent a "strategic inventory shock" for the U.S. military, potentially impacting its ability to project power and maintain deterrence in the long term, especially as it faces other geopolitical challenges.