South Korea Suspends THAAD Deployment

The new president of South Korea has halted the deployment of a controversial missile defense system designed to protect the country from incoming enemy missiles. The Terminal High Altitude Air Defense system, or THAAD, was agreed to by the previous administration as a means to defend both South Korea and the U.S. troops based there from North Korean missile attack.

Earlier this year South Korean President Park Geun-hye agreed to the deployment of the US-made THAAD missiles to her country. South Korea had waffled for years on the deployment, which was urged by the Pentagon, but the breakneck pace of North Korea's missile tests—and what appeared to be an imminent nuclear test—forced the country's hand.

President Park was impeached and removed from office this spring on corruption charges. The new president, Moon Jae-in, has criticized the previous administration's decision to deploy THAAD, saying it it should have been left to the new, incoming president to decide. U.S. President Donald Trump exacerbated the problem by claiming he would present Seoul with a billion dollar bill for THAAD, a boast that was reversed by National Security Advisor H.R. McMaster.

 pair of THAAD launch vehicles, each with eight interceptor missiles, was deployed earlier this year on a South Korean golf course, along with the AN/TPY-2 X-band missile defense radar. This provided a defensive umbrella of 16 interceptors but is short of the six launch vehicles and 48 interceptor missiles a THAAD battery typically deploys with. The battery has achieved "limited initial operations capability," meaning it has some capability to shoot down incoming missiles.

Meanwhile, China went on a full-tilt economic and diplomatic offensive against the THAAD deployment. China fears that the AN/TPY-2 radar has enough range to view all the way into Chinese territory, giving the U.S. a heads-up on any Chinese missile attacks. Beijing also worries that the radar could be used to spy on Chinese airspace and is concerned that it would look politically weak if the United States deployed a new, powerful weapons system in China's sphere of influence. China has organized economic boycotts of South Korean businesses, particularly Lotte, the corporation that owns the golf course.

President Moon claims he was under the impression only two THAAD launch vehicles would be sent and that his administration was blindsided by the deployment of the four vehicles necessary to bring the THAAD battery up to full strength. Moon has said that while the two original launchers may continue operating, the four new ones must wait until a "full-blown environmental impact assessment" was completed.

It's unclear why an environmental impact assessment is necessary: the additional launchers constitute only about four to eight heavy trucks and their crews. South Korean citizens living near the proposed battery originally expressed worry that the AN/TPY-2 radar system could pose health risks, but the number of radars—one—stays the same.

Moon appears to be using the new launchers to buy time for his presidency to organize its own THAAD policy. A former army commando and human rights lawyer, Moon was ambiguous about THAAD during the campaign and while he was careful not to offend the United States, he was also conciliatory to North Korea.

The incomplete deployment of THAAD could cause a rift in the US.-South Korean alliance. The THAAD battery is designed to operate at full strength and cannot adequately do its job—particularly against the hundreds of short and medium range ballistic missiles owned by North Korea—with just 16 interceptors. While there was previously some room for doubt about the need for THAAD, the pace of North Korean missile testing in 2017 has made the need for a ballistic missile defense system clear. Finally, if the U.S. believes that South Korea is not allowing it to adequately protect the 28,500 U.S. military personnel in South Korea from missile attack, it weakens the argument for them to be there in the first place.

This gets to the root of the problem: The problem is not THAAD and the United States, it's the North Korean missiles that make them a necessity. Making THAAD less effective or even making it go away won't make North Korean missiles go away. The Moon administration will eventually greenlight the deployment of the remaining launchers, but a fully-capable THAAD battery on the Korean peninsula likely won't happen any time soon.