Peace at Last: Iran War Has Heavily Depleted America's Munitions

The United States’ war against Iran has finally begun to yield good news. Washington and Tehran have reportedly reached an agreement to end the conflict that has lasted for several months. The news was announced directly by US President Donald Trump and Pakistani Prime Minister Shehbaz Sharif, who acted as a mediator in the negotiation process. The peace agreement is said to be officially signed in Switzerland on Friday. Trump even stated that all points of the agreement with Iran have been completed and are ready to be finalised. Meanwhile, Sharif mentioned that the pact includes a permanent cessation of military operations on all conflict fronts, including in Lebanon. Although the final details have not been published, the agreement is said to reopen the Strait of Hormuz, the vital global energy trade route that has been affected by the war for months. Additionally, the US naval blockade of Iranian ports will also be ended. However, behind the peace news, the war over the past few months has left a heavy burden on the US military. One of these is the significant depletion of ammunition and missile stocks. Citing an analysis by the Center for Strategic and International Studies (CSIS), bombing actions against Iran by the US military and the launch of US air defence system missiles to repel Iranian counterattacks over three months of war have drained a number of Washington’s critical ammunition supplies. CSIS noted that the US fundamentally still has sufficient ammunition to face various scenarios in a war against Iran. However, the massive use in the conflict has created new vulnerability gaps, especially if the US has to face another conflict in the Western Pacific region. In other words, the main problem for the US is not just whether it still has missiles or not. The bigger issue is how quickly Washington can replenish the weapons stocks that have been used during the war. US Secretary of Defence Pete Hegseth previously stated that the process of replenishing weapons inventories would take months to years, depending on the type of weapon system. The CSIS analysis paints a similar picture. One of the most widely used munitions by the US in the war against Iran was the Tomahawk Land Attack Missile (TLAM). CSIS estimates that the US used more than 1,000 Tomahawk missiles during the conflict. This number is very large compared to its annual production capacity. Current Tomahawk production capacity is estimated at around 600 missiles per year, although the target capacity within the US defence industrial framework could reach 1,000 missiles per year. The problem is that production cannot immediately surge in a short time. CSIS notes that with current delivery projections, the US Tomahawk stock is only expected to return to pre-war levels by late 2030 to early 2031. This means that for this single missile type alone, the US needs about four to five years to fully restore its stock to pre-Iran war levels. Besides Tomahawk, air defence systems such as Patriot and THAAD are also in the spotlight. These two systems are important because they are used to intercept missile attacks and protect US and allied military assets. For Patriot, CSIS estimates the US used around 1,060 to 1,430 missiles during the war. Yet, deliveries to the US inventory in fiscal year 2026 are only around 172 units. The US government then requested the procurement of 3,203 Patriot missiles in the fiscal year 2027 budget. However, large deliveries from this procurement are only expected to begin arriving in 2029. CSIS estimates the US Patriot stock will only return to pre-war levels around mid-2029. Meanwhile, for THAAD, the US is estimated to have used around 190 to 290 interceptors. This figure is also quite large, considering the current annual production capacity is estimated at only around 96 units, although the future capacity target could reach 400 units per year. The US THAAD stock is estimated to recover only by mid to late 2029. For naval defence missiles, CSIS highlighted the use of SM-3 and SM-6. Neither was used as much as Tomahawk, Patriot, or THAAD, but they remained an important part of the war as they relate to warship defence and missile interception. The US is estimated to have used around 130 to 250 SM-3 missiles during the Iran war. With a fiscal year 2027 procurement request of 214 units, the stock of these missiles is expected to return to pre-war levels by early 2029. Meanwhile, SM-6 usage is estimated to have reached 190 to 370 units. The US requested the procurement of 540 units in the 2027 budget, with current annual production capacity around 239 units and a future target of up to 500 units. CSIS estimates the SM-6 stock will only recover by late 2028 to early 2029. Not all munitions require years to replace. CSIS notes two types of weapons, namely JASSM and PrSM, have relatively faster recovery times. For JASSM, the US is estimated to have used more than 1,100 missiles during the war. Although the number is large, its stock is expected to return to pre-war levels by mid-2027. This is because deliveries from previous procurement were quite substantial. As for the PrSM or Precision Strike Missile, it is estimated that around 40 to 70 units were used. Its stock is projected to recover faster, by late 2026. However, CSIS notes that the initial PrSM stock was still low because this weapon system has only recently begun production.