​The United States' New Missile Gap

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China and Russia have very large missile inventories.

While Japan, Taiwan and South Korea have Patriot systems, and Japan and the US have AEGIS ballistic missile interceptor s, such as the SM-3, the total inventory of sea-based SM-3s is around 330 missiles (Combined Block IB and Block IIA), far below what might be required in the Pacific region. The SM-3 was used for missile defense in the Twelve-Day War (June 2025) in the Middle East, where 80 were fired. The stockpile is dangerously low.

In Operation Epic Fury around 100 to 150“upper tier” interceptors were used by the United States, or about 25% of the total stockpile. Upper Tier means both SM-3 and THAAD. Writing in War on the Rock s, authors Christopher J. Watterson and Peter J. Dean say that in a Pacific conflict the US would run out of interceptors in twenty four hours.

Israel has a similar problem and is running short of Arrow-3 interceptors. For that reason, Israel has handed off part of its air defense to the system called David's Sling. The difference is profound. While Arrow-3 intercepts missiles in the exoatmosphere, 100 km in altitude (62 miles), David's Sling intercepts are at much lower altitude, between 7 to 15 km ( 4 to 9 miles), meaning that if a missile is hit, debris from the missiles, even its warhead, may survive and strike land targets.

Even more dangerous, it is around these altitudes that cluster-munition ballistic missiles release their submunitions, creating a complex intercept problem that current technology cannot overcome when the cluster submunitions are dispersed.

Israel's missiles are manufactured in partnership with US companies and therefore can face some of the same bottlenecks and delays as US-only products. A significant complicating factor is that the call-up of Army reserves in Israel has reduced the critical home labor force needed by Israel's defense industries.

The way ahead

There are other countries that manufacture missile defense systems including Eurosam (a consortia of MBDA and Thales) that produces SAMP/T which can defend against tactical ballistic missiles like Russia's Iskander series, but the number of deployed systems is relatively small (around 20 units with two in Ukraine and two in Singapore). Eurosam current is producing around 100 interceptors in 2026, an increase over previous levels of around 60.

South Korea is also producing its own air defense hardware with at least three distinct systems under the banner of Korean Air and Missile Defenses (KAMD). L-SAM is the latest but while operating at a higher altitude of 50 to 60 km it won't be available until 2027 at the earliest. Meanwhile a medium altitude system, M-SAM is deployed, and a lower altitude version (LAMD) is said to be like Israel's Iron Dome. M-SAM achieved its first hit against Iranian missiles in Operation Epic Fury in the UAE in March.

Congress mandates some changes

The FY2026 National Defense Authorization Ac, which incorporates the SPEED Act, made a number of changes to accelerate weapons production, remove red tape in the procurement process, and seek standardization for some critical missile components.

One of the most consequential ideas was to seek a common foundation for missile seeker heads hardware and software. The basic idea is to use common hardware with software defined architecture, instead of different hardware and software for every missile system in the inventory. This is an important proposal provided it can be executed and defense companies cooperate to achieve it.

It may take a number of years to come up with a prototype that is sufficiently“plug and play” that the new hardware and software can be used to update existing missiles. The plan is to adapt this for all missiles, such as air to air missiles like Sidewinder (AIM-9), Javelin and SM-6.

A second plan is a push for electronics standardization called the SHIP progra (State of the Art Heterogeneous Integrated Packaging). The idea is a common chipset (called a chiplet) that can be used in various systems instead of custom-designed chips for each system. Intel recently delivered SHIP Program Prototypes six quarters ahead of schedule. a promising development.

Congress also is mandating a common rocket motor program, at least for 21 inch diameter rockets that are used as second stage motors. Both Northrop Grumman and Raytheon have been awarded contracts to develop motors with the common motor footprint. The project is aimed at having a common motor that can be plugged into missile families such as SM-6 Block 1B and forthcoming hypersonic interceptors. Similarly, efforts are underway to standardize rocket ignition systems and thrust vector control interfaces for steering missiles.

Accelerated production of missiles

In the proposed Trump administration $1.5 trillion dollar defense plan, hefty production increases are in the works. The Precision Strike Missile (PrSM), which replaces ATACMS and is fired by HIMARS and M270 launchers, production will be quadrupled from current levels if the funding is approved.

In FY2027 the US would manufacture 1,134 PrSMs at a cost of $1.7 million each. In the same plan, Tomahawk cruise missile production for the US Navy will get a 1200 percent increase. In 2026 only 58 Tomahawks were manufactured. The proposed procurement will raise the number to 785. The current Tomahawk inventory is under severe strain.

Meanwhile, The Pentagon, in partnership with Lockheed Martin and Boeing, is executing a seven-year plan to triple production of the Patriot Advanced Capability-3 (PAC-3) MSE missiles from roughly 600 annually to 2,000 by 2030. For SM-3, the U.S. Department of Defense is partnering with RTX (Raytheon) to significantly increase SM-3 (Block IB and IIA) production through 7-year framework agreements, aiming at two to four times output.

The plan includes investing in manufacturing capacity, accelerating production timelines, and increasing funding for FY2027, with a specific focus on boosting SM-3 IIA production for Japan and the U.S. Navy.