THAAD is not a new topic as it has been in contention since the 1990s. However, when people discuss THAAD, there is always a misunderstanding as to the reach of THAAD. In fact, the reach of THAAD depends on how conspicuous the target is.
For example, it is very easy for human beings to see a pig, but to see a mosquito we need to go very close. When it comes to detecting a missile, some missiles may be big and easily visible to THAAD, while some may be small and cannot be detected if they are far away from THAAD.
When a radar wave touches a warhead, the wave will be reverberated back to the Radar Cross-Section (RCS). The radar wave is the path of detecting an object. If the RCS is too small, it has to be very close to a target, but if it is very big, it can still detect the target from a long distance.
That coverage of the radar depends on the distance between the radar and the target, just like how far you can see depends on the distance between you and your target. As different countries have different skills in making radars, whether a missile can be detected or not depends on the feature of the warhead. The sharper the warhead is, the less likely it is to be detected by the radar.
Currently, when China does the missile flight tests, the direction is always from east to west, because we are sensitive to the feelings of countries like South Korea, and don’t want them to feel threatened. However, now China can only optimize the warhead of the missile instead of the afterbody, so when the afterbody of the missile faces THAAD, it will be detected by THAAD anyway no matter how sharp the warhead is.
But if South Korea deploys THAAD, China will have to change the direction of its missile tests into west-to-east in order not to be detected by THAAD, which will make South Korea feel uncomfortable.
China is not punishing South Korea on purpose. Instead, it is a typical security dilemma. If South Korea deploys THAAD, China has to take its own security into consideration, but China’s security threats will inevitably harm South Korea’s security.
Of course there is a solution to this dilemma for South Korea, which is only installing the interceptor, and using the radar created by South Korea instead of the THAAD radar. This move will not affect South Korea’s capability to deal with North Korea, while it will ease concerns of China.
THAAD can only intercept midrange missiles, which can hardly protect South Korea. If North Korea wants to attack South Korea, a short-range missile will work.
In fact, South Korea is just trying to find a balance by deploying THAAD. South Korea cannot do nothing in the face of North Korea’s midrange ballistic missile program, because people in South Korea will be dissatisfied if the government does nothing. I think South Korea doesn’t want to deploy THAAD either, and is getting a lot of pressure now.
Therefore, South Korea can choose to deploy only the interceptor, through which it can show it is only targeting North Korea and is not posing a threat to China. However, America may get dissatisfied with South Korea’s deployment of its own radar instead of THAAD, because on the one hand deploying THAAD radar is more convenient than deploying other radar; on the other hand, South Korea can get rid of America’s control to a large extent by using its own radar system.
Besides, by not using THAAD radar, America can also ease tensions with China. Confrontation with China is very exhausting, as America already has a lot of things to handle in its own country.
I hope South Korea can be smarter. Even if it deploys THAAD, there is still much room to make adjustments when it comes to concrete implementation.
The author is a professor at Tsinghua University.
(Opinions expressed in the article don't represent those of the Sino-US.com.)