A prolonged conflict between the US-Israel alliance and Iran could prove costly for both sides. The United States depleted more than 20% of its Terminal High Altitude Area Defense (THAAD) missile stockpile during last June's exchange with Iran. Experts say managing weapon inventories will be decisive in determining the outcome of this war.
According to foreign media reports on the 2nd, Iran appears to be at a relative disadvantage in terms of weaponry. The Financial Times reported that since last June's so-called "12-day war," 200 Iranian missiles have been destroyed and dozens rendered inoperable. During the US-Israeli airstrike on Iran on the 28th of last month (local time), forces focused on neutralizing weapon systems including missile launchers scattered across Iran. According to Israel's Alma Center analysis, Iran had only about 100 operational mobile launchers before the current war began. While Iran reportedly possesses around 2,000 medium-range ballistic missiles, the actual usable number may be lower.
However, the United States also faces concerns about missile stockpile shortages in a prolonged conflict. Standard military strategy requires three THAAD missiles to intercept a single Iranian missile.
The FT reported that "the United States used up to 150 THAAD interceptors last year to defend Israel." Given that the US military has possessed a total of 650 THAAD missiles since 2010, this represents roughly one-fifth of its inventory. Stacie Pettyjohn, director of the defense program at the Center for a New American Security (CNAS), noted: "If Iran launches successive large-scale missile and drone attacks, the US military could exhaust a year's worth of defensive missiles in just one to two days of operations."
The challenge is that Iran's weapons are not the only missiles the US must intercept. The Wall Street Journal noted that "repeated clashes with Iranian proxy forces including Hezbollah and Yemen's Houthis have gradually depleted air defense supplies such as Tomahawk Land Attack Missiles (TLAM)."
Ultimately, "inventory management" is identified as the key factor determining not only victory but whether the conflict will be prolonged. Jonathan Conricus, former spokesman for the Israel Defense Forces, analyzed: "The key is quantity. It's a contest between the number of offensive and interceptor missiles."