As the US pauses the war with Iran, is Trump really running out of weapons?

More than 1,000 Tomahawks have been fired during the war, the CSIS estimates, and the stockpile may not return to pre-war levels until 2031. According to the CSIS, the latest variants of the TLAM cost approximately $2.6m (£2m) per missile.Of the air defence systems used in the war, the most heavily used was the Patriot, a ground-based missile used to target aircraft, as well as ballistic and cruise missiles. According to the CSIS estimate, as many as 1,430 were used during the conflict from an estimated pre-war stockpile of about 2,330. Each Patriot interceptor costs approximately $4m (£3.1m) - an expensive but effective option repeatedly used to shoot down Iranian drones that themselves only cost between $20,000-50,000 each (£15,600–£39,000).These will be hard to replace. "It takes several years to produce a missile. If you put money into the system today, you wouldn't get a missile for three or four years. Sometimes even five," Cancian says. "What we're getting [now] are missiles that were funded in 2023."Also used was a newer, more sophisticated system known as Terminal High Altitude Area Defense, or THAAD, which has a longer range and higher intercept altitudes than the older Patriot. Supplies were already limited, with CSIS estimating that between 190 and 290 were fired out of an estimated pre-war stock of 360. With only nine THAAD batteries operational in the world - and seven of them American - sustained expenditure could leave US forces without a system that would be critical to defending ballistic missile threats from countries such as Russia, China or North Korea.All eyes on Taiwan and the PacificThe war with Iran comes just before what is often referred to as the "Davidson window", in which a Chinese effort to invade Taiwan becomes, in the eyes of some US military planners, more likely.The controversial concept - which is central to US military thinking in the Pacific - stems from a 2021 congressional hearing in which Admiral Philip Davidson, then in charge of US forces in the region, warned that an invasion would happen "in the next six years." In 2023, then-CIA director William Burns predicted China would be ready to invade by 2027.