Foreign Policy

US builds missile defense system for South Korea, causing more tension


Terminal High Altitude Area Defense (THAAD), the ballistic missile defense system that the United States recently began constructing in South Korea, is intended to protect the South from North Korean aggression. Instead, it is likely that the system will antagonize China — whose cooperation will be necessary to defuse tensions on the Korean peninsula — and provoke North Korea, all without providing the South with a reliable defense against a full-scale attack.

If the U.S. is serious about improving South Korea’s security, it should negotiate to freeze Pyongyang’s nuclear program instead of deploying a defense system that will be shakily effective at best and that might start a nuclear war at worst.

{mosads}THAAD is designed to intercept short, medium and intermediate range missiles as they descend towards their targets. A standard THAAD battery is comprised of truck-mounted launchers carrying interceptors, a fire control and communications unit, and a radar system. THAAD’s radar has a 120-degree field of view and can detect incoming missiles at a distance of 1,000 km.


Proponents of THAAD’s deployment argue that South Korea needs a more robust missile defense system to protect it from Pyongyang’s advancing nuclear and missile programs. Currently, South Korea deploys U.S.-produced Patriot missile defense systems, which have a limited capability and are insufficient to protect the entire country. However, it is not clear that THAAD can completely fill in the gaps.

After a very poor record with six test failures in a row in the 1990’s, THAAD has successfully intercepted its targets in 11 out of 11 tests since 2006, but these tests are highly scripted to maximize the system’s chance of success. In its most complicated test to date, THAAD cooperated with Patriot and Aegis defense systems to down five ballistic and cruise missiles. Although this test was considered integrated, each missile defense system operated separately, and THAAD only intercepted one medium-range ballistic missile.

THAAD has not been independently tested against more than two ballistic missiles and was not designed to defend against cruise missiles.

Meanwhile, it is estimated that North Korea has 1,000 ballistic missiles, between 10 and 16 nuclear weapons, and one of the largest arsenals of chemical weapons in the world. If Pyongyang attacked South Korea, the North, knowing that an American counter-attack was inevitable, would be incentivized to use all of its weapons. We don’t know whether THAAD can intercept three incoming missiles, let alone hundreds. And if these missiles carried chemical or nuclear weapons, even one missile that evaded the defense systems would cause catastrophic damage.

Furthermore, THAAD has blind spots that an adversary could exploit. The U.S. has agreed to provide South Korea with one THAAD battery, whose radar, if north-facing, would cover the North Korean mainland. However, because THAAD’s radar can only cover 120 degrees at a time, North Korea could circumvent the system by launching a submarine-launched ballistic missile (SLBM), a weapon it successfully tested last year, from any point not covered by the radar.

Nor would THAAD be useful as a deterrent measure. China has already warned that THAAD’s deployment may spark an arms race in the region, as North Korea and potentially China develop more advanced missiles that could evade THAAD’s radar.

China has raised concerns that the U.S. will use the system’s radar to glean information about Chinese military activities. Despite repeated U.S. explanations that THAAD is purely defensive, China continues to argue that the missile battery is harmful to its national security. If China acts on its professed fears, THAAD deployment will mean a more complicated and volatile situation in the region.

Tensions on the Korean Demilitarized Zone continue to rise, and deploying THAAD batteries, which will give South Korea little additional protection from attack, will likely exacerbate the situation.

There is little evidence that our relationship with allies would be undermined by its removal. Even South Korea was not particularly excited about THAAD’s introduction to the region, delaying the decision to deploy the system by two years before agreeing in 2016. Moreover, deploying THAAD will antagonize China at a moment when, if we hope to address North Korea’s ballistic missile and nuclear programs, we need Beijing’s cooperation more than ever.

In contrast to diplomatic negotiation — the method preferred by numerous experts, former defense and military officials, and many members of Congress — THAAD cannot freeze or reverse North Korea’s nuclear program. In fact, the opposite is true. THAAD may be a defensive system, but that doesn’t mean it can’t trigger a war.

Philip E. Coyle is the Senior Science Fellow at the Center for Arms Control and Non-Proliferation. He served in top security roles in the Clinton and Obama administrations and previously was a top official at the Lawrence Livermore National Laboratory. Bernadette Stadler is a Herbert Scoville Jr. Peace Fellow at the Center for Arms Control and Non-proliferation.

The views of contributors are their own and not the views of The Hill.

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