July 13, 2016
THAAD Deployment in South Korea
Understanding the Implications for Strategic Stability
By Alek Chance
On July 13, 2016, the Republic of Korea (ROK) announced the planned deployment of a U.S. Terminal High Altitude Area Defense (THAAD) system. This deployment is a result of a stated U.S. desire to bolster allied defenses against a possible North Korean (DPRK) missile attack, particularly after the DPRK’s nuclear test in January 2016. The Chinese government has condemned the deployment and warned that THAAD could raise tensions in the area.
What is THAAD?
THAAD is an American ballistic missile defense system (BMD) that integrates an X-band radar, a command and control center, and up to six missile batteries in separate road-mobile units. The radar detects incoming ballistic missiles and provides targeting information to the missile launcher. A THAAD missile then intercepts and destroys the incoming ballistic missile in its final or “terminal” stage in high atmosphere or just outside the atmosphere. The system, especially the radar, contains very advanced technologies.
The THAAD issue touches on the question of nuclear strategic stability. Both the US and China have taken steps recently to improve their nuclear arsenals or to alter their strategies. This has resulted in uncomfortable adjustments in the nuclear relationship. BMD inherently challenges nuclear strategic stability insofar as it raises the possibility, however small, that the possessor of BMD can avoid retaliatory attacks by an adversary. This degrades the adversary’s confidence in its deterrent and thus increases the value of preemptive attacks for both sides (strategic instability). While the United States and China effectively have a relationship of mutual deterrence at the nuclear level, only China explicitly embraces a “no first use” policy. In the Chinese perspective, the United States manipulates ambiguity in this regard in order to exercise coercion. This perception may frame Chinese interpretations of American willingness to alter the strategic balance with a THAAD deployment. The THAAD issue also reflects upon problems of mutual mistrust. Chinese analysts cannot see the utility of THAAD for addressing the DPRK threat and infer the system is thus directed at China. Similarly, Americans who cannot understand Chinese objections to THAAD assume the real issue is that China wishes to limit U.S./ROK cooperation or American defense capabilities in general.
Chinese Concerns about THAAD in South Korea
Chinese officials contend that THAAD threatens China’s legitimate security interests and could destabilize the region. In February 2016, Chinese Foreign Minister Wang Yi argued that the deployment of the THAAD system by the United States … goes far beyond the defense need of the Korean Peninsula” and that it “is not just to defend South Korea, but a wider agenda and may even serve the possibility of targeting China.” After its deployment was announced in July 2016, Wang called THAAD “unjustified” and reiterated that the system “far exceeded the need for defense and will undermine the security interests of China…and shatter the regional strategic balance and trigger an arms race.”
These concerns are grounded in a few Chinese perceptions. First, many Chinese strategists do not consider THAAD to be a suitable defense against DPRK missiles, given the short distances involved and DPRK limitations. Because of this, the assumption is made that THAAD must be intended for some other use. Second, THAAD’s radar is capable of detecting and tracking missile launches within parts of mainland China. While a THAAD system in South Korea is not thought to be capable of intercepting Chinese missiles, the THAAD radar can be integrated into other existing missile defense systems in order to improve their effectiveness by providing early tracking or discrimination information. This presents the possibility of degrading China’s second-strike (retaliatory) nuclear deterrent capabilities. Finally, South Korean participation in an integrated missile defense program would mark a further strengthening of what China often perceives to be American “encirclement” with its alliance system.
The American View
American officials emphasize that North Korea is the sole concern behind a proposed THAAD deployment in South Korea. The US State Department has expressed concern about advances in the DPRK’s missile program. During a visit to Beijing, US Secretary of State John Kerry emphasized that THAAD is a “purely defensive weapon.” The US believes that THAAD is an appropriate countermeasure to some DPRK missiles. It contributes to a “layered” BMD program that guards against all angles of attack, including a possible detonation of a nuclear warhead at high altitude—something which ROK
defenses cannot currently prevent.
In response to China’s concerns about its nuclear deterrent, American officials have stressed that the US does not intend for any BMD system to counter sophisticated missile systems such as those possessed by China. BMD is meant to counter less advanced arsenals like those of the DPRK or Iran. American commentators and officials have also noted that X-band radars have already been placed in Japan and Alaska, and that a THAAD radar would add very little to US surveillance capabilities over the Chinese mainland. Some Americans have argued that the radars would function in “terminal mode” (scanning for missiles in their terminal phase) and thus would not be able to scan relevant areas of China. Others, like MIT’s Ted Postol, have argued that THAAD’s radar engages in both functions simultaneously and that it has no distinct “modes.” China’s recent development of nuclear missile-armed submarines also reduces the value of such surveillance capabilities and ensures the survivability of China’s second strike forces.