South Korea and Japan in the Trump Era

South Korea currently faces a number of challenges to its security and regional stability. The political and economic rivalry between China and the new U.S. administration, along with an increasingly aggressive Japan and North Korea, have shifted the geopolitical landscape in Northeast Asia. To address these challenges, South Korea should pursue two tactics. First, it should renegotiate the deployment of the THAAD missile system and instead develop better military capabilities for the Republic of Korea Armed Forces. Second, it should partner with the United States and Japan to pressure China to take a tougher stance against North Korea.

Japanese Prime Minister Shinzo Abe visited the United States in early February 2017 to begin building a relationship with the new U.S. President Donald Trump. Facing fierce criticism from neighboring countries on his intention to reform its pacifist constitution, particularly revision of the military clause in article 9, Prime Minister Abe hoped to get full support from President Trump. Japan’s movement has alarmed South Korean leaders and policymakers, as a militarized Japan could provoke an arms race and bring back fears of Japanese imperialism.

While Japan was quick to reassure President Trump of the strategic importance of their alliance, South Korean leaders have yet to meet with President Trump in person to discuss his administration’s stance on South Korea-related policies. Furthermore, President Trump’s more belligerent foreign policy agenda has put South Korea in the difficult position of taking a stronger stance against China, even though it is not in South Korea’s interests to aggravate its relationship with China due to potential economic and political retaliation. Another major issue for South Korea is that it still lacks a head of state; President Park was impeached and ousted by the constitutional court in March 2017 and a new president will not take office until mid-May 2017. Nevertheless, South Korea can stabilize its situation by leveraging negotiations around THAAD to develop the Republic of Korea Armed Forces and joining forces with the US and Japan to force China to increase pressure on North Korea.

Military negotiations will likely center around finalizing the deployment of the THAAD missile system in South Korea. Given China’s strong opposition to the missile defense shield, South Korea could use THAAD deployment as leverage in military negotiations with the United States. Instead of deploying the THAAD missile system, the South Korean government can negotiate with the Trump administration for the expansion of the South Korean army’s military capabilities or financial and technical assistance for developing South Korea’s own missile defense system. Since THAAD maintenance and operation costs will be borne primarily by the U.S. military forces in Korea, this action could play to Trump’s interests by reducing the financial burden on the United States.

Meanwhile, it is important that South Korea develops its own missile defense system to justify withdrawing THAAD. To do so, South Korea should progressively increase its military budget to at least 3% of the GDP from 2.4% of the GDP as of 2015. With a larger budget, South Korea can accelerate the development of a domestic missile defense system like the South Korean Kill Chain System, which is expected to be completed in 2023. Simultaneously, South Korea should persuade the Trump administration to actively oppose Japan’s militarization. Japan has referenced the North Korean threat as one of the reasons it should reform the non-militarization clause in the constitution. South Korea can argue that with its own greater military capabilities, the North Korean threat is not a credible excuse to justify the militarization of Japan.

The second tactic South Korea should pursue is working with the US and Japan to involve China more deeply in the North Korean crisis. Despite UN economic sanctions against North Korea in March 2016, North Korea conducted another long-range missile test in February 2017. One of the main reasons for the ineffectiveness of the measures is China’s reluctance to fully enforce sanctions. China needs its alliance with North Korea in the region to offset pressure from the United States and its Asian allies. Because of China’s non-cooperation, many are skeptical that UN sanctions will be an effective deterrent on their own. As a result, the United States and Japan have actively supported the deployment of THAAD in South Korea as an alternative. Whereas the Obama administration was more prudent in dealing with North Korea in order to avoid conflict with China, President Trump has openly denounced China for encouraging North Korea’s nuclear aggression. Since it seems likely that the Trump administration will take a more hostile stance against North Korea, Japan and South Korea will no longer be alone in arguing for stricter sanctions and commitments against North Korea. This is a crucial opportunity for South Korea to present a united diplomatic front against the North Korea threat with the other members of the Six Party Talks. If faced with a united regional opposition, China may be pressured to take a stronger stance on North Korea’s nuclear and missile development, which could help bring down the level of tension on the Korean Peninsula.

The changing landscape from Japan and the United States presents South Korea with an opportunity to define policy actions to defend its interests. The rivalry between China and the United States is likely to grow, and North Korea is becoming an increasingly dire security threat that may force cooperation. South Korea’s foreign policy must be strong enough to face these challenges while being flexible enough to cope with a rapidly changing arena. Renegotiating the deployment of the THAAD missile system would give South Korea the opportunity to deflect criticism from the Trump administration and China while refuting Japan’s attempts for legitimizing its militarization. In addition, South Korea should use President Trump and Prime Minister Abe’s closer relationship and the two leaders’ opposition to North Korea’s nuclear program to pressure China to take a harsher stance toward North Korea and comply with sanctions.