Shortly after assuming office, the new Trump administration will undertake a comprehensive review of the missile threats confronting the United States. Geopolitical and technical developments are undermining the longstanding foundations of U.S. missile defense policy. Potential adversaries such as Russia, China, Iran, and North Korea are deploying an expanding portfolio of ballistic, cruise, and hypersonic missiles—supplemented by large fleets of reconnaissance and strike drones. These countries are pooling their resources in the missile domain. Both Iran and North Korea give Moscow missiles and drones to use against Ukraine, while Russia is assisting these partners’ aerospace programs. Meanwhile, technology is transcending delineations between regional and homeland missile systems.

Some beneficial changes have already occurred. The Pentagon is deploying a Next-Generation Interceptor before the end of this decade. The new interceptor will make the Ground-based Midcourse Defense system protecting North America from intercontinental ballistic missiles more effective. The Missile Defense Agency has launched a new Transformation Task Force to evaluate options for realigning missions and responsibilities, integrating cross-domain capabilities, modernizing digital technologies, improving internal agency processes, and enhancing cooperation with operational forces and other partners.

Advances in U.S. missile defense capabilities have been evident in the wars in Ukraine and the Middle East. The United States can leverage these technologies to build a more comprehensive missile shield. However, budget constraints and competing priorities could degrade capabilities and increase risks.     

In particular, U.S. defenses against hypersonic missiles are lagging. The Chinese and Russian militaries are constructing several types of hypersonic conventional and nuclear delivery systems capable of traveling at many times the speed of sound. The Defense Department’s latest China military power report assesses that “The PRC has the world’s leading hypersonic missile arsenal.” Russia has employed several hypersonic missiles against Ukraine, including its new Oreshnik intermediate-range ballistic missile in December.

Chinese and Russian leaders perceive hypersonic weapons as providing their countries with critical strategic and operational capabilities. At the strategic level, long-range hypersonic glide vehicles flying unpredictable trajectories in the upper atmosphere can circumvent existing U.S. national missile defenses. At the regional level, hypersonic cruise and ballistic can quickly destroy high-value targets such as U.S. command centers, military bases, and forward-deployed forces.

The United States needs a well-constructed plan to parry these hypersonic threats. The Defense Department is developing constellations of Hypersonic and Ballistic Tracking Space Sensor satellites to provide continuous coverage of hypersonic vehicles in flight. The Pentagon is further assessing a software program to upgrade the Long-Range Discrimination Radar under construction to identify hypersonic targets. 

But seeing and tracking fast maneuvering gliders in the upper atmosphere is only half the problem. The United States also needs to shoot them down. Congress has established a deadline for the United States to field an initial hypersonic interceptor capability by the end of this decade. The Pentagon is accordingly building the first system optimized to attack hypersonic gliders. Though a novel capability, this Glide Phase Interceptor (GPI) leverages proven technologies that the Navy has used to shoot down hundreds of missiles and drones in the Middle East. 

Unlike U.S. offensive hypersonic missile programs, which have experienced repeated technical setbacks, defensive efforts have been primarily budgetary rather than technologically constrained. The Pentagon spends less annually on hypersonic interceptors than it does on a pair of new F-35 fighters. Funding limits have compelled the Pentagon to curtail R&D contacts for engaging hypersonic gliders.

Meanwhile, proposals to divert the limited funding to build a “gap-filler” terminal interceptor with constrained capabilities have arisen to provide patchwork protection until the GPI is deployed. Though terminal interceptors shielding a few critical sites could help build a layered defense, funding for any gap filler should supplement rather than divide the budget for the GPI, which will protect a much wider area.

The GPI program also has built-in burden sharing. The Japanese government is allocating $368 million to support its development through a Cooperative Development agreement with the United States and other means. The president and Congress should leverage these matching funds to support a rigorous GPI development, testing, and deployment program.

Richard Weitz is a Senior Fellow and Director of the Center for Political-Military Analysis at Hudson Institute. His current research includes regional security developments relating to Europe, Eurasia, and East Asia, as well as U.S. foreign and defense policies. Before joining Hudson in 2005, Dr. Weitz worked for several other academic and professional research institutions and the U.S. Department of Defense, where he received an Award for Excellence from the Office of the Secretary of Defense.

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