This post is authored by Terence Roehrig, professor of national security affairs and director of the Asia-Pacific studies group at the U.S. Naval War College. It is part of a project conducted by the program on U.S.-Korea policy at the Council on Foreign Relations, supported by the Smith Richardson Foundation and Korea Foundation. This series of posts will address the U.S. nuclear posture in Northeast Asia, implications of North Korean nuclear and missile programs for U.S. extended deterrence commitments, operational and tactical dimensions of deterrence on the peninsula, and regional dimensions of stability. To further stimulate an open discussion of these issues, we would like to invite reader responses. Please contact Ellen Swicord at firstname.lastname@example.org for submission guidelines if you are interested in contributing a response.
Efforts to seek the denuclearization of North Korea continue and it is unclear how this story will end. The results of the Hanoi summit have done little to generate more hope for success. The fundamental question –is North Korea willing to denuclearize– remains unanswered. Optimists argue that more U.S. concessions are needed to reduce tensions and coax Pyongyang to relinquish its nuclear weapons. Pessimists maintain that North Korea must first show concrete signs of its willingness to denuclearize before benefits can follow, and believe Pyongyang has no intention of doing so. I remain doubtful that North Korea can be convinced to give up its nuclear weapons, but that it is worth trying to see what might be possible and to avoid the heightened tension levels of 2017. In any case, the likelihood of a single “big deal” that settles all of the outstanding issues related to denuclearization is very small; this will be a process that spans years, even if successful.
In the meantime, South Korea, Japan, and the United States must decide how to balance the next steps to seek North Korean denuclearization with the continued need to maintain a strong deterrence position that ensures peace and stability as denuclearization efforts play out. Military postures on the peninsula have already been part of the process, as demonstrated by the North-South Comprehensive Military Agreement, and the changes to the timing and scope of ROK-U.S. joint military exercises. Calibrating the correct balance between tension reduction measures and maintaining defense readiness will be difficult and viewed differently in Seoul, Tokyo, and Washington. Disagreements over the best approach to dealing with North Korea persist and, unfortunately, relations between Japan and South Korea are in a dreadful state, making these decisions all the more challenging.
The U.S. military works well bilaterally with its partners in Japan and South Korea. Both alliances have in place numerous structures, planning processes, and regular meetings at all levels that ensure close collaboration and a robust, dynamic deterrence posture. Over the past decade, numerous initiatives have been undertaken by both alliances to update responsibilities and improve planning and responses for cyber and nuclear events, along with addressing lower-level North Korean provocations.
The challenge lies with cooperation across these two alliances and developing mechanisms for increased tactical and operational collaboration between all three partners. Given the state of Japan-South Korea relations, which is at one of its lowest points in years, prospects for further cooperation are bleak. Any new trilateral effort will need to be modest and maintain a low profile. Moreover, these measures must avoid being provocative and undercutting the denuclearization process, while also demonstrating a credible deterrence commitment and maintaining regional security.
First and foremost, the foundation for better military-to-military cooperation is improved relations between Japan and South Korea. The long history of animosity between Seoul and Tokyo continues to obstruct military cooperation. The comfort women issue remains a problem, and the ruling by South Korea’s Supreme Court awarding damages to ROK laborers forced to work for Japanese corporations during the occupation has caused further friction. Matters worsened when Japanese officials reported that a South Korean destroyer locked its fire control radar on a Japanese maritime patrol aircraft, an accusation Seoul has disputed. Until some of these issues are resolved or set aside and relations improve, prospects for military cooperation will be significantly limited.
Despite these obstacles, there are a few areas where Japan and South Korea might be able to increase military cooperation in dealing with North Korea in the future. Seoul, Tokyo, and Washington have two important intelligence sharing agreements in place, the Trilateral Intelligence Sharing Agreement (TISA) and the General Security of Military Information Agreement (GSOMIA), to provide for greater intelligence collaboration. These agreements have improved strategic-level intelligence sharing, but more work at the tactical and operational levels would be useful. One possibility is increasing cooperation on dealing with the ship-to-ship transfer of petroleum and other commodities to North Korean vessels that evade UN sanctions. These efforts could be part of a broader multilateral coalition that reduces the domestic political costs for South Korea and Japan.
Second, increased cooperation on ballistic missile defense (BMD) is also a potential area to help address the North Korea challenge. Both naval forces have Aegis-class destroyers; Japan has six and South Korea has three, with plans to build three additional vessels. Japanese Aegis destroyers are equipped with SM-3 interceptors that are top-of-the-line BMD shooters. South Korean vessels are armed with the SM-2 interceptor that is largely designed as an anti-air and cruise missile defense weapon. In October 2018, the ROK Joint Chiefs indicated the intention to purchase the SM-3 to upgrade its BMD capability. Critics have argued that the SM-3 is not useful for defending against North Korea’s short-range missiles that do not reach the necessary altitude for the SM-3. In addition, BMD capabilities in general have significant limits.
Others maintain that the SM-3 would be important to counter medium-range Nodong missiles launched with an elevated trajectory that could target the peninsula. In June 2018, Chief of U.S. Naval Operations Admiral John Richardson indicated that the U.S. Navy would drastically scale back its BMD operations, while remaining available for emergencies. Increased BMD cooperation between Japan and South Korea could help fill the gap as the U.S. Navy turns to other missions.
However, BMD cooperation faces several big hurdles. Due to objections from China, South Korea has maintained an independent BMD capability that is not tied to the U.S. regional BMD architecture. Japan is an enthusiastic participant in U.S.-led BMD efforts, but South Korea is reluctant to join in. When South Korea agreed to accept a U.S. Terminal High Altitude Area Defense (THAAD) system to the peninsula, China quickly reacted by retaliating against the ROK economy. Eventually, the Moon administration made peace with China. In return for keeping THAAD and Beijing easing up on its economic pressure, Seoul agreed to the three no’s: no further THAAD deployments, no participation in the U.S. BMD system, and no trilateral military alliance with the United States and Japan. Thus, BMD cooperation between South Korea and Japan will be a difficult undertaking.
South Korean and Japanese naval forces have often been in the unique position to work together despite enmity at higher levels. Military leaders understand the need for security cooperation and have done their best to foster a better operational relationship that is less public and susceptible to the turmoil of domestic politics. Exercises between the two forces improve their ability to operate together and deconflict their actions in a combat situation. Increasing their frequency and scope can help promote even better cooperation. Unfortunately, these efforts have been complicated by ROK protests over Japanese ships flying the “Rising Sun” ensign, and Tokyo’s subsequent withdrawal from South Korea’s international fleet review in October 2018.
What can the United States do about this? Washington must not be a bystander. The United States plays a central role in this trilateral relationship and must actively engage with Japan and South Korea to bridge differences, work to pursue their many common interests, and help manage the issues likely to remain thorny for the foreseeable future. U.S. officials must be careful and utilize quiet diplomacy, because allowing relations to deteriorate further while standing on the sidelines will be a disaster. Improved relations at the highest levels will be essential for increased cooperation at lower levels.
At the operational level, bilateral exercises and operations will be nearly impossible to hold, but multilateral ones organized by others may provide the political cover for both parties to improve joint operations. As noted above, Washington could increase multilateral maritime cooperation to enforce economic sanctions that would include Japan and South Korea, but not highlight this as a trilateral operation. Other operational tasks could be approached in a similar manner.
Increasing trilateral cooperation between Japan, South Korea, and the United States will be very difficult. All three disagree over the proper mix of pressure and concessions regarding North Korean denuclearization, and relations between Seoul and Tokyo have rarely been more strained. Maintaining an appropriate deterrence posture will be important given the uncertainty of where the denuclearization process goes. At the same time, tension levels have decreased and the deterrence postures on both sides of the DMZ will be part of the ongoing deliberations. Increased trilateral defense cooperation is unlikely to occur anytime soon and will require improved ties at higher levels. Given the circumstances, maintaining current efforts at cooperation may actually be the most reasonable goal. When Japan-South Korean relations improve, more may be possible, but much will depend on the progress, or lack thereof, in denuclearizing North Korea.
The views expressed in this article are those of the author, expressed in an unofficial capacity, and do not reflect the official policy or position of the Department of the Navy or the U.S. government.