Since South Korea decided to deploy the Terminal High Altitude Area Defense (THAAD) missile defense system in 2016, Sino–South Korean relations have been strained. Beijing has levied unofficial economic sanctions and diplomatic pressures on Seoul with the hope that it will withdraw THAAD. China strongly believes that the deployment of THAAD on the Peninsula will undermine its deterrence capabilities against outside powers — especially the United States.

South Korean President Moon Jae-in in May 2017 ordered a probe into the unannounced arrival of four THAAD launchers in South Korea, raising questions over the government’s position on the controversial defense system. But there are at least three reasons why South Korea will not withdraw THAAD easily.

One is Seoul’s relationship with the United States. THAAD has become a new litmus test of the US–South Korean alliance. Although President Moon has said that he would like to say ‘no’ to the United States, THAAD might be the last item on that list.

Second, there is the bureaucratic establishment in the Moon administration that supported THAAD. Moon will have to work through many different South Korean bureaucracies — especially in the military — to run the government effectively. Withdrawing THAAD might damage his relations with elements in these bureaucracies and thereby damage his government’s efficacy.

Finally, there is the cost to credibility and reputation. The deployment of THAAD has not been free. The United States has agreed to pay the equipment, maintenance and operational costs of THAAD. By withdrawing THAAD, Moon would potentially expose South Korea to huge monetary losses in violating its agreement with the United States, as well as psychological losses in credibility and reputation regarding the nation’s resolve against the North.

Furthermore, changing a policy is more difficult than sticking to an existing one — changing policies involves more risk. Moon was just elected and is still in a ‘domain of gains’. International leaders are less likely to take risks when they are in an advantageous situation, so if withdrawing THAAD is a risky decision, there is no reason to expect Moon to take it.

Along similar lines, since South Korea did gain some deterrence capabilities from THAAD, it is unlikely to ‘correct’ the Park administration’s perceived failings in missile defense. Most international leaders tend to be loss averse, so the forfeiture of THAAD’s deterrence capabilities would be felt more strongly than the easing of Chinese and Russian retaliation measures.

China’s intense economic and diplomatic pressures might also play a counterproductive role in changing South Korea’s policy. Here, nationalism kicks in. The THAAD issue involves emotion, national pride, and even irrational sentiment in South Korea. If consternation over Chinese pressure amplifies, then Moon will be unable to withdraw from THAAD without earning the ire of his constituents. That sort of negative escalation in sentiment would be a true tragedy, not only between the two states but also among peoples in the two societies.

If Moon is placed in a higher-risk scenario due to changing domestic or international dynamics, he might be more willing to change his THAAD policy. But without a change in policy, how will China and Russia respond? They would likely have no choice but to deploy some countervailing missiles and radar systems to restore the military balance on the Peninsula, which could lead to an unfortunate arms race in Northeast Asia.

There are no easy options for Moon. While he remains in the honeymoon period of his administration, it is unlikely he will accept the risks of changing THAAD policy.

Kai He is Professor of International Relations at Griffith Asia Institute and Centre for Governance and Public Policy, Griffith University.

This first appeared in East Asia Forum here.

Image Credit: Reuters.