Can THAAD Save South Korea?

A Terminal High Altitude Area Defense (THAAD) interceptor is launched from a THAAD battery located on Wake Island. Flickr/U.S. Missile Defense Agency

South Korea’s current defenses against a North Korean missile attack grow porous as Pyongyang’s nuclear and missile capabilities improve. THAAD improves things, but only a bit.

Since South Korean President Park Geun Hye’s decision to deploy the THAAD (Terminal High Altitude Area Defense) missile defense system in South Korea earlier this year, public discourse has flared intensely over the issue. Dozens, maybe hundreds, of editorials, both in favor of and highly critical, have appeared in Korea’s major newspapers. Analysts have invoked Thucydides to explain it. The conservative Saenuri party speaks of THAAD as a paradigm shift.

But the South Korean left has gotten the most carried away, where deployment of a single THAAD battery with just 8-10 anti-missile rockets, has morphed into great powers once again kicking around Korea. There have been marches, protests, and activists shaving their heads. A regular anti-THAAD protest has sprung up next to the U.S. embassy in Seoul. The main opposition elected a new leader, Choo Mi-Ae, who buoyed her appointment with a strong anti-THAAD message. The left’s presidential candidate of 2012, Moon Jae-In, called for halting the deployment. There is talk of using THAAD as a campaign issue in next year’s presidential election.

This is so much sturm und drang over very little – heavily fanned by China, which knows very well how little THAAD changes things and why South Korea wants it. THAAD changes almost nothing geopolitically. It is a defensive system intended recapture the status quo ante against Northern missilization. It does not facilitate American or South Korean offensive action against North Korea or China. Its X-band radar may ostensibly reach into China, as Beijing claims, but other U.S. systems can already determine a Chinese missile launch, so X-band adds nothing. South Korea is only buying one THAAD battery, which has only 8-10 rockets. That battery will not, as a concession to the China, cover Seoul. THAAD also does nothing to reduce North Korea’s conventional, artillery-barrage choke-hold on Seoul.

Next, THAAD has never been battle-tested. No one really knows how effective it will be. But even if all ten THAAD anti-missile rockets were to destroy Northern inbound  missiles, the North almost certainly has, or will soon have, many more, including dummies. Finally, THAAD is only a mild quantitative expansion of what South Korea already has. It is not a qualitative shift in regional air battle scenarios. South Korea’s current missile defense capabilities, the Patriot PAC-2 (soon to be PAC-3), reach up an altitude of 40 kilometers, while THAAD can reach around 150 kms. If Beijing and the South Korean left are correct, adding an extra 110 kms of middle defense range is bringing down east Asian stability. This is preposterous.

In reality, THAAD just thickens South Korea’s “roof” a little. It buys South Korea a few more years at best – a bit more time before North Korea builds so many missile, drones, dummies, and so on that it can overwhelm Southern air defense. THAAD does not obviate the North’s nuclear weapons, much less China’s. It just gives Seoul a little more breathing room to figure out what to do about Pyongyang’s spiraling missile program. This minor addition to Southern defense kicks the can of Northern nuclear weapons down the road while everyone scrambles to figure out what to do before air-strikes become a serious option.

Opponents suggest that THAAD will increase North Korean and Chinese anxiety, spurring reprisals. Perhaps, but those are worth the risk now that North Korea is so close to nuclear-tipped missiles and is likely on track to build dozens in the next decade. And it is North Korea’s missile and nuclear programs which are the real challenges to otherwise stable conventional deterrence on the peninsula. Nuclear missilization gives North Korea a growing asymmetric advantage. Failing to respond would leave South Korea more vulnerable to nuclear blackmail, or a nuclear first strike in case of crisis escalation and conflict. Whatever the risks of THAAD deployment, the risks of inaction are greater. THAAD can help mitigate those risks without offensively threatening South Korea’s neighbors.