The military used one fourth of its THAAD interceptors to defend Israel. Imagine how many it would need to defend Taiwan.

This summer’s “12-Day War” between Israel and Iran exposed what Washington should have long known: the US military’s air and missile defense architecture is not ready for a long fight against a capable enemy. Israel severely degraded Iran’s ability to fire missiles by systematically eliminating many of their launchers. However, the United States still expended nearly 25 percent of the total number of Terminal High Altitude Area Defense (THAAD) anti-ballistic missile interceptors during the short conflict. Not a quarter of all our THAAD interceptors bought last year, but a full one-fourth of all of these systems ever procured. The military is falling behind and must reverse course soon.

In the twelve days of fighting between Israel and Iran, over 150 THAAD interceptors were launched at Iran’s more advanced ballistic missiles. This is over three times the average annual procurement of around 40 interceptors since 2010. At $15.5 million per interceptor, this puts the armed forces on an unsustainable trajectory. Even if the Pentagon increases current orders beyond the meager 12 funded in the 2025 budget, it still takes 3 years between the date a contract is awarded and when the interceptors are delivered.

The shortage of THAAD interceptors is not unique. American ships in the region also launched over 80 Standard Missile-3 (SM-3) interceptors to help defeat Iranian missiles during the 12-day conflict. The only version of this missile in production is the SM-3 Block IIA, and the Defense Department is still waiting on the first delivery of these upgraded missiles from a contract awarded in 2019.

The United States used a significant portion of its interceptor stockpiles to defend Israel, which has its own multi-layered air and missile defense systems, from Iran. This rogue state had already lost half its missile launchers from Israeli strikes, according to the Israeli government. Now, imagine a fight with China.

Much has been written about how a shortage of offensive munitions will make it difficult for the United States to outlast a sophisticated military in any prolonged conflict. Not only are American munitions stockpiles limited, but also the means of delivery are decreasing as our fleets of surface warships, fighter jets, and bombers continue to shrink in size.

The US Air Force used nearly half of its stealth B-2 fleet just to strike the Iranian nuclear site at Fordow in Operation Midnight Hammer. Our offensive platforms are limited, and defending them against attacks by missiles and drones would be crucial to successfully defeating any Chinese aggression. While it may seem odd to fire a million-dollar interceptor to defeat a thousand-dollar drone, it makes sense to fire as many interceptors as necessary to defend a multi-billion-dollar ship against that drone.

If the Iranians can deplete 25 percent of America’s THAAD stocks and a significant portion of our SM-3 magazines in a few days, the Chinese can and will exhaust them in a few hours. Multi-million-dollar missiles, only produced in the dozens per year, are no match for far cheaper and more plentiful threats. America cannot stay on the losing side of the production curve when it comes to missile defense. At a time when the risks of a protracted conflict with a peer rival are growing, the military must regain its ability to compete at scale.

The most promising solution for the fastest return is to leverage commercial innovation. Our free market system, access to capital, and entrepreneurial culture make the United States the envy of the world for technological innovation. Washington must do more to leverage this advantage to develop novel interceptors and non-kinetic defenses that are designed from the outset for production at a scale of thousands per year.

But the transition to more mass-produced missile defense systems will not happen overnight, and policymakers should not view it as an either-or choice. The US military can bridge this transition by adopting a hybrid approach, following the example of the Space Force. Services must continue to build next-generation, exquisite systems while initiating multiple efforts to develop lower-cost, highly proliferated systems with new companies. A mix of capabilities will, over time, bolster stockpiles while strengthening and broadening the defense industrial base.

With the influx of money just appropriated for the Golden Dome, the Pentagon finally has the resources it needs to pursue a hybrid approach to missile defense. The initial Golden Dome architecture, due any moment, should make mass-produced systems a key element of the overall design.

Look no further than artillery to find this blended production model already underway and showing early success. Congress has been pouring money into the armed forces’ organic and defense industrial bases for munitions, and those investments are starting to pay off. The Army has been busy investing billions in new munitions production lines and adding new capacity and resiliency to its supply chains across the country. In parallel, the Army is “expanding and modernizing existing facilities to increase speed, flexibility and capacity.”

As the US Army succeeded in quadrupling the monthly production rate of 155mm shells this summer, it also expanded surge capacity by “moving shell production from a single facility to four separate facilities this year.”

This milestone came on the heels of another new load, assembly, and pack munitions facility that opened in Arkansas in April. A late May ribbon-cutting at Crane Army Ammunition Activity in Indiana for a new explosive railcar holding yard also followed.

The American defense industrial base revitalization is underway. The managed decline that took place over decades, however, will take more funds and more time to reverse entirely. The US commercial industry is ready and able to join the fight. The only thing we lack is time.