Table of Contents


The fraught security implications of tensions between North and South Korea rightfully occupy a great deal of attention. The possibility that these tensions could drive intervention by or even conflict between outside powers cannot be overlooked. Given its long-standing alliance with South Korea, or the Republic of Korea (ROK) and leading role in the diplomatic push to get North Korea to relinquish its nuclear weapons, the United States understandably factors heavily into such calculus. But China deserves special consideration given its substantial interests and influence on the Korean Peninsula and growing military prowess.

China’s interests on the Korean Peninsula still carry a lot of weight. North Korea remains an important Chinese partner because it continues to act as a buffer between China and South Korea (and the U.S. troops it hosts). Beijing would naturally go to great lengths to ensure that any diplomatic progress between Pyongyang, Seoul, and Washington does not undermine aspects of this status quo that it finds advantageous. At the same time, Chinese leaders are keen to capitalize on ways that such diplomacy could erode the institutional foundations of the U.S.-led security order on the peninsula. As China’s leaders move more deliberately to protect their country’s interests, they have an increasingly powerful hand to play. Beijing has undertaken a highly ambitious military modernization campaign to facilitate and complement its growing tendency to act more assertively to advance its equities on the Korean Peninsula.

While South Korea’s own interests undoubtedly diverge from China’s in significant ways, Seoul can hardly write off the prerogatives of its massive neighbor entirely.

While South Korea’s own interests undoubtedly diverge from China’s in significant ways, Seoul can hardly write off the prerogatives of its massive neighbor entirely. Instead President Moon Jae-in and his administration must pursue diplomatic reassurance and hard-nosed security reforms along multiple tracks that will sometimes be in tension with each other. On the one hand, Seoul must stay in close coordination with Washington to both optimize diplomatic overtures to Pyongyang and ensure that the alliance can prove its mettle if such outreach fails. On the other hand, South Korea must avoid antagonizing China outright even as it contends with the far-reaching implications of China’s more active military footprint on its doorstep. Threading this needle will be a long-term enterprise that requires all the diplomatic acumen and strategic foresight that Moon has at his disposal.

China’s Interests on the Korean Peninsula

China’s views on the Korean Peninsula are refracted through the lens of geopolitics, international law, and history. In geopolitical terms, Beijing sees the situation as a theater of regional competition with the United States. Because China cooperates more closely on economic and security matters with North Korea than any other nation in the region, it can use stable relations with North Korea to maintain and expand its influence on the Korean Peninsula.

When the administration of U.S. President Donald Trump unveiled its Free and Open Indo-Pacific strategy as a pointed rejoinder to Beijing’s own regional vision amid escalating U.S.-China tensions, North Korea’s value to China rose further as fears in Beijing of U.S.-led encirclement increased. China believes that the Trump administration is further accelerating the establishment of a regional coalition to curb China’s growing political, economic, and military influence. Consequently, China has an interest in discouraging neighboring countries from participating in the U.S. strategic vision for the Indo-Pacific. Chinese President Xi Jinping and the government he leads are seeking to establish a system favorable to China’s interests instead of adapting to the U.S.-centric international order.

Jina Kim
Jina Kim is chief of the North Korean Military Division and a research fellow at the Korea Institute for Defense Analyses, specializing in U.S.–North Korea relations, nuclear nonproliferation, and Northeast Asian security.

It is with this mentality that China is keeping an eye on South Korea’s response to the Free and Open Indo-Pacific strategy. The Moon government proposed linking South Korea’s New Northern Policy with the China-led push to fund regional infrastructure through the Belt and Road Initiative. Seoul seems to be seeking to highlight the common ground between the Moon-championed peace process pursued by South Korea and China’s regional goals.1 However, many Chinese experts believe that South Korea demonstrated that its true loyalties lie with the United States when it agreed to allow the United States to deploy the Terminal High Altitude Area Defense (THAAD) missile defense system on the peninsula.2 The flexibility of South Korea’s position will be constrained as the United States increases the pressure on Seoul to choose between it and China. As these trends play out, China is likely to respond to developments on the Korean Peninsula not in isolation but through the overarching prism of U.S.-China competition.

Given these geopolitical stakes, China unsurprisingly argues that it has a legal right to be involved in inter-Korean relations as a party to the Korean War and as a signatory of the Korean Armistice Agreement that ended open hostilities.3 In 2016, Chinese Foreign Minister Wang Yi expressed China’s interest in hastening negotiations for an end-of-war declaration and a peace treaty to replace the armistice agreement.4 On some level, China has pursued this stance because it sees the ongoing denuclearization negotiations as the best chance for disarmament on the Korean Peninsula, but there are more realist, hard-nosed interests at play too.

The nature of the institutional foundation undergirding the U.S. military presence in South Korea adds another layer to China’s diplomatic position. The temporary but long-standing armistice agreement provides legitimacy for maintaining the United Nations Command (UNC).5 UNC is a U.S.-led command that was established by the United Nations (UN) Security Council to defend South Korea against the North Korean invasion in 1950. When the Combined Forces Command (CFC) was founded in 1978 and became the command tasked with defending South Korea in the event that conflict resumed, UNC was relegated to maintaining the armistice rather than fighting a war. Because the command’s task is to maintain the armistice, replacing that temporary measure with a permanent treaty would remove UNC’s current mandate. Beijing, as a signatory of the armistice treaty, would likely advocate to dissolve UNC rather than adjust its mandate because there would be no armistice to keep.6

The dissolution of UNC would eliminate one of the three U.S.-led commands, including the United States Forces Korea and CFC, on the peninsula. China has long wanted to see the UNC structure dissolved or at least weakened, including UNC–Rear located in Japan, a critical support mechanism for allied military operations to defend South Korea. In the UN General Assembly Resolution 3390B submitted in 1975, China called for the dismantlement of UNC and the withdrawal of all foreign troops stationed in South Korea.7 At that time, the UN General Assembly supported negotiations toward a peace treaty to replace the armistice as soon as possible, and South Korea and the United States agreed to keep UNC until an alternative mechanism was formed to achieve a final peace settlement.8 Given this history, China will continue to link the discussions on signing a peace treaty to the issue of dismantling UNC.9

Dissolving UNC would not significantly affect the combat capabilities of U.S.–South Korean allied forces on the peninsula itself, but it could significantly hinder U.S. reinforcements from being sent via Japan in the event of a conflict on the Korean Peninsula. In addition to a status of forces agreement (SOFA) for the stationing of U.S. forces in Japan, some of the UN Sending States (among the nations that provided forces and support to UNC during the Korean War, including the United States) have a separate SOFA for UNC–Rear called the UN-Government of Japan SOFA.10 This SOFA allows a subset of UN members—including Australia, Canada, France, New Zealand, the Philippines, Thailand, Turkey, the United Kingdom, and the United States—to use several UN/U.S. bases to transit through or operate from Japan in the event of a regional contingency. This arrangement is crucial to U.S. force flow and to maintaining a stable center of command in the event of a conflict on the peninsula.

Moreover, the SOFA requires nations to notify the Japanese Ministry of Foreign Affairs of any use of the bases, though its terms do not technically require Japanese approval for such activities. While it is highly unlikely that the United States and partner nations would not request Japanese approval, abolishing UNC would require this SOFA to be renegotiated; if that happened, it is unlikely that any signatory of the current SOFA would be able to negotiate such generous terms again. Additionally, for as long as it remains active, UNC could lend legitimacy to international coalition contributions to support the U.S.–South Korea alliance’s efforts to conduct military operations in times of crisis. This is one consideration to bear in mind as China continues to pursue conversations with North Korea parallel to ongoing United States– and South Korea–led negotiations on the denuclearization of the Korean Peninsula and the establishment of a peace regime. China’s status as party to agreements concerning UNC through its position as a permanent UN Security Council member gives China legitimacy to influence the discourse on the changing alliance, including the status and role of the U.S. troops based in South Korea, under international law.

This state of affairs influences how Beijing portrays the ongoing dispute over Pyongyang’s nuclear program. China argues that North Korea’s nuclear ambitions stem from the country’s decades-old isolation and anxiety about the regime’s potential collapse.11 As a suggested remedy, China urges improvement in U.S.–North Korea relations and the reduction of military threats so as to supposedly alter North Korea’s strategic outlook and encourage denuclearization. Framing the situation in this way serves China’s interests by providing a rationale and incentives for reducing U.S. capabilities and troop levels in Northeast Asia.

On a related note, China recently secured a diplomatic success with regard to U.S.-ROK military exercises. China has long advocated for a freeze-for-freeze deal that would suspend North Korea’s nuclear and missile tests in exchange for curbing large-scale joint U.S.-ROK military exercises. In a surprise to the Pentagon and many observers, Trump proposed this very arrangement unilaterally at the Hanoi summit with North Korea in February 2019. Consequently, large-scale joint U.S.-South Korea military exercises have been replaced with smaller drills. This policy change already has caused concerns about a slight degradation in military readiness of CFC, the combined U.S.–South Korean war-fighting command.12

As a next step, Beijing may demand other concessions from the alliance such as a reduction or withdrawal of U.S. military forces stationed on the Korean Peninsula. China has maintained that all U.S. troops should be withdrawn from the Korean Peninsula as Chinese forces were under the armistice agreement.13 Beijing has pointed out that, unlike China, the United States has ignored its treaty obligation while deploying a large number of weapons systems to South Korea, which Chinese officials claim contributes to the regional arms race. China is concerned that the United States is criticizing North Korea’s military build-up while strengthening its own military posture in the region, with the goal of pressuring Beijing. Given these considerations, China will keep on opposing U.S. attempts to strengthen its military alliance with South Korea.

China’s Military Posture, Modernization, and Exercises

As they seek to improve their own strategic positioning, Chinese leaders continue to reject any attempt to shift the balance of power on the peninsula in ways that benefit the United States and South Korea. To this end, China is actively adopting a more proactive, far-reaching defense posture and modernizing its military to alter the military balance in Northeast Asia and optimize its influence on the Korean Peninsula. China’s response to the situation on the Korean Peninsula should be examined in the context of this revised military posture, its ambitious military modernization, and its more active military presence near the peninsula.

A More Expansive Military Posture

Amid intensified competition with the United States, China has focused on projecting military power overseas especially in the maritime domain. This strategic shift has important implications for nearby neighbors, including South Korea. In general terms, China’s military aims to “build . . . a strong national defense and powerful armed forces,” overarching goals laid out in its 2015 white paper.14 This document focuses predominately on China’s “maritime rights and interests,” and it specifically cites the U.S. rebalance to Asia strategy and Chinese concerns about Japan as reasons for paying greater attention to this subject. Specifically, Beijing is concerned about rapid Japanese modernization across its ground, maritime, and air forces and the restart of parliamentary debates on revising the country’s postwar peace constitution, which put the genie of Japanese militarism back in the bottle.

The white paper explicitly added a new goal of protecting China’s overseas interests, marking an expanded scope compared to previous iterations that focused on security threats closer to home from what the Chinese government refers to as “separatists” in Taiwan, Tibet, and Xinjiang. In a corresponding change, Beijing made it clear that the operational domain of the Chinese armed forces has expanded, extending to cover the East China Sea, the South China Sea, and parts of the Western Pacific. The inclusion of these theaters signals that China is recalibrating its defense posture to be more external-facing, particularly with respect to the Korean Peninsula. Over the coming years, this more outward-looking posture means that China will likely do more to try to influence the status quo in the region, which in many cases may not support South Korea’s strategic interests. South Korea has been preparing for challenges caused by third-party intervention, especially by China, in case of a contingency on the Korean Peninsula, but Seoul must prepare for these challenges in the context of U.S.-China competition as well.

A More Modernized Military

To this end, China has undertaken a complete modernization of the People’s Liberation Army (PLA) in terms of theory, organizational structure, service personnel, combat readiness, weaponry, and scope of military activities. The overall goal is to make the PLA a world-class military by 2050.15 The Chinese armed forces are tasked with seizing the strategic initiative and actively securing the country’s overseas interests. The Chinese government noted considerable progress on this front in a March 2019 report.16 The PLA shoulders a wide range of strategic tasks. In 2015, the Chinese government outlined eight strategic assignments the PLA must be ready to execute, including the charges of resolutely safeguarding the unification of the motherland; protecting China’s security interests in new domains; and advancing China’s overseas interests.17 The PLA aims to safeguard national security by effectively controlling any crisis that may emerge and its follow-on effects.

Specifically, China seeks to craft a more streamlined military with joint-service capabilities, in which all the services work in tandem. Beijing is pushing to establish an advanced operational apparatus attuned to the needs of modern warfare, make its military structure more efficient, and better train military personnel to perform joint operations. In accordance with these objectives, the Chinese military has reorganized its departments into functional sections under the Central Military Commission and reduced the number of theater commands to five—the Eastern Theater, the Southern Theater, the Western Theater, the Northern Theater, and the Central Theater Commands.18 By the same token, China is striving to shift the PLA from a ground-based force to one in which all the services are highly mobile and coordinate well. To this end, the country has reduced its troop count by 300,000, a move that the New York Times reports will free up funding for sea and air forces, which “require fewer but better trained personnel.”19 

Notably, China is focusing its remaining ground troops in Northeast Asia. The larger Northern Theater Command that has resulted from this strategic shift encompasses Mongolia, the far eastern reaches of Russia, and the Korean Peninsula.20 This means that PLA forces could quickly intervene in Northeast Asian affairs. Given how the PLA has strengthened its ability to respond quickly and operate at long range, South Korean forces would face a heavier burden contending with their Chinese peers if the latter were to actively intervene in Korean affairs. Since at least 2004, China has sought to strengthen its ability to conduct joint operations near the Korean Peninsula.21 China’s recently recalibrated force posture and training exercises, including high-profile naval drills off the Korean Peninsula in December 2016 and August 2017, indicate that the country is prepared to infiltrate the Korean Peninsula by ground, sea, and air if necessary to protect its interests. That said, precisely how these forces would be combined would depend on the actual contingencies at hand.

If a major conflict were to break out, it is also possible that the PLA would pull extra forces from the Central Theater Command. If Beijing did so, it would be seeking to deter the forward deployment of additional U.S. military assets based in the United States to discourage possible escalation and an unwanted confrontation with the Chinese military. It is no surprise, then, that South Korea has major concerns about how the PLA is strengthening its ability to conduct military operations near the Korean Peninsula.

On some level, it is understandable why Beijing would feel compelled to take such steps. China shares an 880-mile long border with North Korea, and the country’s leaders are well aware of the impact an emergency in North Korea could have on China’s own security and internal stability.22 Beijing’s chief concerns center on the risk of a flood of North Korean refugees seeking to cross the border into northeastern China or a loose arsenal of uncontrolled weapons of mass destruction in the event of state collapse or severe unrest in North Korea.23 In any major crisis, China’s first priority would be tasking the Northern Command’s army aviation brigades and special operations forces with securing Pyongyang’s weapons of mass destruction. Given that the relevant known weapons facilities are closer to the Chinese border than to the South Korean border, Chinese forces could do this more quickly than ROK-U.S. combined forces.24

As China seeks to transform the PLA into an expeditionary force, its military modernization is overwhelmingly focused on the maritime and air domains. The modernization of the PLA Navy includes the development and production of new surface vessels and new submarines, a change in line with the military’s strategic goal of improving its operational capabilities.25 The PLA Air Force is seeking to modernize its military aircraft including fighter jets, aerial refueling tankers, and transport planes to enhance its ability to deploy aircraft quickly, support them effectively, and secure the airspace at the border in case of a crisis. In particular, the next-generation J-20 fighter jet is intended to improve the country’s air defense capabilities.

The expansion of the PLA Navy Marine Corps, which began in April 2017, requires analytical attention too.26 China’s Marine Corps is expected to be a 30,000-strong force by 2020, and its mission will likely grow “to include expeditionary operations on foreign soil.”27 Previously, the Marine Corps were assigned only to the South Sea Fleet stationed in Zhanjiang in Guangdong Province. Marine Corps units can now be found all along China’s eastern seaboard all the way to Shandong Province in the north. A former army motorized infantry brigade of the former Twenty-Sixth Group Army stationed in northern Shandong has reportedly been transformed into a new marine brigade. In southern Shandong Province near the port city of Qingdao, a new second marine brigade has been formed.28 Considering that the North Sea Fleet is known to be tasked with leading the military response to a crisis on the Korean Peninsula, South Korea has legitimate concerns about China’s increasing amphibious and expeditionary warfare capabilities. 

These military changes have affected not just China’s conventional forces but its nuclear forces as well, a number of which are under the Northern Theater Command and could thus come into play in a conflict on the Korean Peninsula. China is also upgrading its nuclear arsenal. Beijing maintains that its nuclear forces are a strategic necessity for safeguarding national sovereignty and security, and the country is prepared for the worst-case scenario of a nuclear confrontation with another nuclear-armed country. Although China traditionally has employed a policy of no first use of nuclear weapons, Beijing still has an interest in optimizing its nuclear force structure, improving its strategic early warning system, projecting power with its missile arsenal, the ability to act quickly under tight time constraints, and maintaining a strong level of deterrence vis-à-vis the United States. To modernize its nuclear forces, China is strengthening its silo-based intercontinental ballistic missiles and improving the viability and mobility of its missiles.29 The Chinese military is also speeding up the development of new technologies including hypersonic glide vehicles to better penetrate ballistic missile defenses. The PLA Rocket Force is pursuing innovations in weaponry and other equipment to strengthen its capabilities in terms of strategic deterrence, nuclear counterattacks, and medium- and long-range precision strikes. The Fifty-First and Twenty-Eighth Bases of the PLA Rocket Force (some of the units that control China’s nuclear weapons) also report to the Northern Theater Command.

When China clearly maintained a posture of restraint with a modest strategic nuclear force, it was widely believed that Beijing had limited deterrence goals.30 But the scope and scale of China’s nuclear modernization has renewed questions about its intentions, raising the possibility that the country may be looking to move from a modest strategy of minimum deterrence to a more robust strategy of assured retaliation even without formally changing its policy against first use.31 When China has a wider range of options for engaging in a war, it could have the flexibility to wage damage-limiting strikes aimed at preventing escalation to an all-out war and winning a limited conventional war. Preparing for various nuclear scenarios such as initiating a surgical strike on lines of communications or logistic nodes to delay force movement is complex, considering the process of determining threats and making decisions to choose an appropriate response. Besides, China’s increased capabilities to strike rival military bases could change U.S. allies’ perceptions and effectively diminish strategic stability, which would increase the risks of escalation and could undermine U.S. extended deterrence in East Asia.

The loss of a key nuclear weapons treaty has heightened Beijing’s sensitivity to the nuclear balance of power in East Asia. Until the United States and Russia scrapped it in 2019, the 1987 Intermediate-Range Nuclear Forces (INF) Treaty had eliminated Russian and U.S. ground-based missiles with ranges between 500 and 5,500 kilometers. One reason the United States left the INF Treaty is that some policymakers in Washington felt that China’s short- and medium-range missiles should be subject to the same restrictions imposed on the INF Treaty’s signatories. U.S. decisionmakers worried that Beijing’s military modernization has allowed it to field short- and medium-range missiles so as to prevent the United States from intervening militarily in geographic areas near the Chinese mainland.32 By extension, the fear is that China may exercise preemptive strike capabilities against U.S. military bases in Northeast Asia.33 This line of thinking has been used as justification for the United States to potentially station nuclear forces in Asia, a possibility that China is very concerned about.

After the Trump administration announced that the United States would pull out of the treaty, Beijing criticized Washington for disrupting regional stability.34 With new flexibility to station short- and medium-range nuclear-armed missiles in Asia, one country in which the United States could potentially station such nuclear forces is South Korea. On the one hand, this might provide added deterrence for South Korea against the North Korean threat. But if Seoul were to agree to let the United States station such missiles in South Korea, China would see that move as highly escalatory. China has shown willingness to retaliate economically against South Korea against even the deployment of U.S. defensive systems like THAAD, and the stationing of nuclear-armed missiles in South Korea would almost certainly provoke a similar or even more severe response. Beijing will continue to pressure U.S. allies in Asia to not deploy U.S. ground-based nuclear weapons.

To sum up, these various changes to the Chinese military have profound implications for South Korea and allied U.S. forces. As a consequence of U.S.-China strategic competition and growing fears of instability in North Korea, China is shifting its military focus to the Korean Peninsula. At the same time, neither Seoul nor Washington’s defense establishments have positive relationships with Beijing for the purpose of coordinating planning for North Korean contingencies. This could create a scenario in which all three countries’ militaries are operating in a conflict without prior consultation and disparate strategic goals. This state of affairs greatly increases the potential for accidents or miscalculation in the event of a crisis on the peninsula. Even in the absence of conflict, Beijing’s adjustments to its military posture could weaken the U.S.-ROK alliance by increasing the stakes for Seoul as it tries to navigate its relationship with its largest trading partner, China, and its most important ally, the United States. Amid unrelenting competition between China and the United States, China will keep trying to get the ROK to refrain from conducting military exercises with its ally or deploying new U.S. capabilities.

Change of Practices

In conjunction with its more expansive military posture and rapidly modernizing military forces, China has altered its operational behavior in several notable ways. For starters, Beijing has bolstered its ability to conduct maritime reconnaissance missions with a new vessel designed for this purpose. In January 2017, China commemorated the launch of the PLA Navy’s new intelligence-gathering ship, the Haiwingxing, which is capable of conducting all-weather, around-the-clock reconnaissance on multiple different targets.35 The new ship supports China’s North Sea Fleet, joining two other intelligence-gathering ships deployed in 1989 and 2015, respectively. The Haiwingxing’s deployment confirms the Chinese navy’s increasing ability to conduct multiple, widely dispersed operations simultaneously in the region. This addition to the fleet may not directly increase tensions with China’s neighbors, but it could invite other countries (including South Korea) to more determinedly assert their own rights to conduct naval and intelligence-gathering operations.

More broadly, in recent years, the PLA has increased patrols near the Korean Peninsula. Between January 2016 and February 2019, Chinese warships intruded into South Korea’s exclusive economic zone (EEZ) 465 times, or 84 percent of the total such incursions (see figure 3).36 This naval activity became more prevalent over time. In 2016, there were 110 Chinese intrusions into South Korea’s EEZ, a figure that more than doubled to 243 cases in 2018. These heightened incursions are certainly, at least in part, a product of China’s close-in air and sea surveillance and reconnaissance activities, though these movements could be meant to serve other purposes too. For instance, Beijing could be aiming to test the South Korean military’s posture and response. Another possibility is that China intends to try to claim effective control of waters near the Korean Peninsula. Specifically, Seoul and Beijing have yet to define an EEZ in the waters near Socotra Rock in the West Sea, which both countries lay claim to, despite many rounds of talks. In South Korea, this submerged rock, which has been the subject of a maritime dispute for many decades, is referred to as Ieodo; South Korea has built a maritime research station and helipad there. Beijing’s attempt to apply military pressure on Seoul is a cause of great concern for South Koreans who worry that China could renew a jurisdictional claim to Socotra Rock.

Aside from maritime surveillance, China has also regularized large-scale naval exercises in the West Sea since 2016 for purposes of power projection, personnel training, and contingency planning.37 When tensions between the United States and North Korea escalated, Chinese military forces held a large-scale training exercise in July 2017 in the Yellow Sea involving aircraft carriers and battle groups. China staged a second naval drill the following month near the Korean Peninsula in Chinese coastal waters from Qingdao and Lianyungang after a major North Korean missile test in late July. These exercises could have been a message to Pyongyang to stand down or a signal to deter other countries from escalating military tensions on the Korean Peninsula. A year later, Chinese theater commands held a round of live-fire exercises and simulated antisubmarine attacks in the Yellow Sea too. China’s domestically designed aircraft carriers were reportedly involved in the exercise because of the drill’s proximity to its home port of Qingdao.38

More frequent Chinese military activity has not been limited to the seas adjacent to the Korean Peninsula. Chinese military planes have violated the Korean Air Defense Identification Zone (KADIZ) more often in recent years too (see figure 4).39 For instance, a Chinese Shaanxi Y-9G reconnaissance aircraft entered airspace claimed by South Korea northwest of Jeju Island in late December 2018. Air defense identification zones (ADIZs) refer to geographically designated air space that countries like China, Japan, and South Korea have arbitrarily established to prevent other countries from violating their airspace, requiring unauthorized aircraft to identify themselves and seek permission to enter in advance. There is no basis for such a designation in international law, but it is international common practice to provide advance notice before entering an ADIZ.

To cite another example, on July 23, 2019, when a Russian warplane violated South Korean air space above the Dokdo Islets, two Chinese H-6 strategic bombers entered the KADIZ without giving prior notice. Denying that any violation of international law had occurred, China explained that the planes were conducting a joint air patrol mission with Russian aircraft in neutral air space.40 Whenever Chinese military aircraft violate the KADIZ, South Korea deploys fighter jets to track and monitor them. South Korea sees the regular intrusion of PLA aircraft as aimed at testing Seoul and Washington’s joint posture and response.

China’s shift to focus on overseas threats, military modernization, and military competition with South Korea’s strongest ally pose a new challenge to the U.S.-ROK alliance. War on the Korean Peninsula is unlikely, but with China’s increasing demonstrations, through increased surveillance and military drills, of its willingness to proactively protect its interests abroad, U.S. allies including South Korea may have less faith in the decisiveness of U.S. military predominance. As pressure to choose between the United States and China grows amid intensifying competition, South Korea is in an increasingly difficult position. To continue prioritizing the U.S. alliance over ties to China, South Korea must be assured that the United States retains the ability to help Seoul withstand Chinese attempts to interfere with its security.


Even as Seoul and its allies in Washington continue to grapple with Pyongyang’s nuclear ambitions, Beijing’s growing military footprint is casting an additional shadow of uncertainty over the security landscape of the Asia Pacific. The stop-and-start nuclear talks with North Korea are an obvious development to watch, despite the uneasy impasse negotiators seem mired in. Yet relevant actors from South Korea to the United States surely remain cognizant of how the shifting security balance in the region seemingly owes at least as much to China’s heightened military capabilities and greater apparent willingness to use them.

For its part, South Korea should strengthen its capacity for maritime deterrence both through its own efforts and in coordination with the United States. As China’s naval might and attempts to tighten maritime control over the waters adjacent to the Korean Peninsula grow, Seoul should also seek to defend its maritime interests. In the near term, South Korea needs to be prepared to respond effectively to the possibility of a small dispute with neighboring countries and the minimum deterrence needed to prevent any provocations, as these are far more likely than any large-scale conflict.

Over the short term, sufficient naval and air forces are already in place to guard against the risk of small-scale conflict within South Korea’s EEZ. In the medium to long term, the South Korean military will have to build up its defense capabilities to discourage armed provocations by neighboring countries. To augment its own efforts, South Korea should coordinate with the United States so Seoul can better engage in joint naval and air operations and improve its intelligence, surveillance, and reconnaissance capabilities by employing satellites and aircraft. Seoul should continue to pursue its Defense Reform 2.0 and U.S. cooperation to develop and acquire advanced military assets and capabilities. 

Seoul and Washington should both understand how important multilateral security cooperation, information sharing, policy consultations, and joint exercises all are to maintaining peace and stability in the region.

The robust U.S.–South Korea alliance remains essential to both nations’ security despite the shifting regional security environment. To keep the alliance strong, the two countries need to expand its scope by promoting South Korea’s ability to make contributions to regional stability rather than orient the alliance solely toward deterring North Korea. Such regional contributions should include peacekeeping operations, counterpiracy operations, reconstruction efforts, humanitarian assistance, and disaster relief.

In this spirit, Seoul and Washington should both understand how important multilateral security cooperation, information sharing, policy consultations, and joint exercises all are to maintaining peace and stability in the region. It is in South Korea’s interest to participate in networked security cooperation with U.S. allies and partners to advance shared fundamental values, improve connectivity, and assist with capacity building. That being the case, South Korea should work to lay out on what terms and to what extent it will help support the U.S. Free and Open Indo-Pacific strategy.

South Korea can tacitly endorse aspects of this vision that call for advancing shared goals such as maintaining the presence of U.S. forces on the Korean Peninsula, continuing negotiations with North Korea on denuclearization, preserving joint readiness to respond with overwhelming force to any attack by North Korea, and preventing unilateral changes to the regional security’s environment. Although these goals are in South Korea’s best interests, the sensitivities of Seoul’s relationship with Beijing would have consequences for any formal endorsement, which may discourage Seoul from signing on to the strategy in the near future.

Collaborative efforts to monitor changes to North Korea’s military capabilities should continue. Sharing relevant information among concerned countries is important in terms of preparing for possible future negotiations on biological and chemical weapons and missile disarmament. It should be noted that the more denuclearization and disarmament discussions proceed, the higher North Korea’s willingness to develop new weapons systems could be. Because North Korea is sensitive to the changing balance of power on the peninsula, North Korea’s interest in developing asymmetric conventional weapons systems will likely grow. This reality makes information sharing on North Korea’s military research and development activities even more important. In particular, it is vital to do more to monitor items banned under international export controls with the eventual goal of bringing North Korea into the global nonproliferation regime. South Korea and the United States can pursue a variety of policy responses to the attendant proliferation challenges such as strengthening sanctions enforcement, updating export control lists, building systemized review processes, and assisting national capacity-building so as to strengthen the international nonproliferation regime.

Confidence-building measures (CBMs) are also an important consideration that China and South Korea should pursue to help ease regional tensions. The key lesson of the THAAD debacle was that strengthening defense cooperation in the Asia Pacific, though intended to deter North Korea, could trigger strategic distrust in China. It is necessary for South Korea to carefully analyze China’s military rise and hold discussions with China on various CBMs and crisis management measures through a security consultative body. To this end, Seoul needs to further internalize regular, high-level security dialogue, which has already been established via multiple channels. These channels include a communication line between the Blue House National Security Office and China’s State Council for Foreign Affairs, vice minister–level strategic dialogues, and director general–level dialogues on foreign affairs and security matters.

South Korea will need to operate deftly to manage the competing prerogatives of keeping the U.S. alliance strong, maintain a stable diplomatic equilibrium with China, and curb the worst excesses of North Korean behavior. A key ingredient of such diplomatic acumen will be a clear-eyed understanding of what China’s key interests are and how it is prepared to employ its growing clout to defend them.

About the Author

Jina Kim is chief of the North Korean Military Division and a research fellow at the Korea Institute for Defense Analyses, specializing in U.S.–North Korea relations, nuclear nonproliferation, and Northeast Asian security. She is the author of The North Korean Nuclear Weapons Crisis (London: Palgrave MacMillan UK, 2014).

The analysis, opinions, and conclusions in this section are solely the author’s own views and in no way reflect any views or positions of the ROK Ministry of National Defense, the Korea Institute for Defense Analyses, or any other branch or unit of the ROK government.


1 South Korean Ministry of Economy and Finance, “Deputy Prime Minister Hong Nam-ki Attends the Second One-on-One International Cooperation Summit Forum,” (press release), April 27, 2019,

2 Chinese scholars called for coercing South Korea to change its position on deploying THAAD, but some also noted that Seoul is an important part of the U.S. rebalancing strategy and hence made such a decision in consideration of its relations with the United States. Yin Chengde, “With THAAD, U.S. and South Korea Are Playing With Fire,” China-U.S. Focus, October 19, 2016,; and Yang Xiyu, “How Should China Retaliate Against South Korea for Its Deployment of THAAD?” Global Times, August 1, 2016.

3 The Preamble of the 1953 Armistice Treaty states that the Commander of the Chinese People’s Volunteers agree to accept and to be bound by the conditions of armistice, identifying China as a signatory of the agreement. See United States Forces Korea, The Korean War Armistice Agreement, Panmunjeom, Korea, July 27, 1953,

Hua Chunying, spokesperson of the Chinese Ministry of Foreign Affairs confirmed China as a concerned party to the Armistice and therefore will play an active role in establishing a peace regime on the Korean peninsula at the briefing on April 18, 2018. Chinese Ministry of Foreign Affairs, “Foreign Ministry Spokesperson Hua Chunying’s Regular Press Conference,” April 18, 2018,

4 Chinese Ministry of Foreign Affairs, “Foreign Minister Wang Yi Meets the Press,” March 9, 2016,

5 Qiu Guohong, “Security Environment of the Korean Peninsula and China’s Policy Toward Korea,” speech at the ROK National Assembly, Seoul, July 10, 2019.

6 The Korean War Armistice Agreement.

7 United Nations Office of Public Information, “United Nationals General Assembly Resolution 3390A/3390B Question of Korea,” Yearbook of the United Nations 1975 November 18, 1975, (New York: United Nations, Office of Public Information, 1978), 203–204. 

8 Ibid. 

9 Chae Jin-lee, A Troubled Peace: U.S. Policy and the Two Koreas (Baltimore: Johns Hopkins University Press, 2006), 78–79.

10 U.S. Air Force Yokota Air Base, “United Nations Command-Rear Fact Sheet,”

11 Shin Kyung-jin, “‘Jung migug-ui bughan anbo ulyeo haeso bal-eon hwan-yeonghanda’” [China welcomes resolving North Korea’s legitimate concerns], Joongang Ilbo, May 18, 2018,; and Kim Kyung-jin, “Jung wang-i oegyobujang “bughan-ui anbo·baljeon-e daehan jeongdanghan ulyeo haegyeoldwaeya,” [Foreign Minister Wang Yi mentioned North Korea’s legitimate security concerns to be addressed] KBS News, December 5, 2019,

12 U.S. Senate Armed Services Committee, Hearing to Consider the Nomination of General Robert Abrams, USA, for Reappointment to the Grade of General and to Be Commander, United Nations Command, Combined Forces Command, and United States Forces Korea; and Vice Admiral Craig S. Faller, USN, to Be Admiral and Commander, United States Southern Command, 115th Cong., (2018) (responses of General Robert Abrams, commander, United Nations Command, September 25, 2018),

13 Yun Sun, “The China-Russia Entente: Impact of Sino-Russian Cooperation on East Asia Security and the United States,” National Bureau of Asian Research, June 14, 2019,; and Sang Lee, “Experts Insist on Multilateral Talks on Nuclear Weapons in North Korea,” Radio Free Asia Korea, June 14, 2019,

14 State Council Information Office, “China’s Military Strategy,” May 2015,

15 Xi Jinping, “Secure a Decisive Victory in Building a Moderately Prosperous Society in All Respects and Strive for the Great Success of Socialism With Chinese Characteristics for a New Era,” at the Nineteenth National Congress of the Communist Party of China, Xinhua News Agency, October 18, 2017,'s_report_at_19th_CPC_National_Congress.pdf.

16 Li Keqiang, “Report on the Work of the Government,” the Thirteenth National People's Congress of the People’s Republic of China, Xinhua News Agency, March 16, 2019,

17 See U.S. Department of Defense, Assessment on U.S. Defense Implications of China’s Expanding Global Access (Washington, DC, U.S. Department of Defense, 2018),

18 “PLA to Announce Overhaul: Five Strategic Zones Will Replace Regional Commands, Most Army HQ to Be Scrapped," South China Morning Post, December 19, 2015, The four general departments that were the headquarters for the entire PLA were replaced by fifteen functional sections under the Central Military Commission, including the Joint Staff Department, the Political Work Department, the Logistic Support Department, and the Equipment Development Department.

19 Edward Wong, Jane Perlez, and Chris Buckley, “China Announces Cuts of 300,000 Troops at Military Parade Showing Its Might,” New York Times, September 2, 2015,

20 The Northern Theater Command includes three group armies, a naval fleet, two marine brigades, two PLA Air Force bases and one PLA Rocket Force base. Office of the U.S. Secretary of Defense, 2019 China Military Power Report (Washington, DC, U.S. Department of Defense, 2019),

21 Office of the U.S. Secretary of Defense, Annual Report to Congress: Military and Security Developments Involving the People’s Republic of China (Washington, DC: U.S. Department of Defense, 2018), 114.

22 United States-China Economic and Security Review Commission, “Roundtable Before the U.S.-China Economic and Security Review Commission,” 115th Congress, April 12, 2018,,%202018.pdf.

23 Ibid.

24 Chung Min Lee and Kathryn Botto, Unification Blue Book: Reconceptualizing U.S-ROK Cooperation in Korean Unification: A Stabilization Framework (Washington, DC: Carnegie Endowment for International Peace, 2019),

25 Elsa B. Kania, “Chinese Advances in Unmanned Systems and the Military Applications of Artificial Intelligence: the PLA’s Trajectory Towards Unmanned, Intelligentized Warfare,” Testimony Before the U.S.-China Economic and Security Review Commission, February 23, 2017,

26 Dennis J. Blasko and Roderick Lee, “The Chinese Navy’s Marine Corps, Part 1: Expansion and Reorganization,” Jamestown Foundation China Brief 19, no. 3 (2019),

27 Office of the U.S. Secretary of Defense, Annual Report to Congress: Military and Security Developments Involving the People's Republic of China.

28 Blasko and Lee, “The Chinese Navy’s Marine Corps, Part 1: Expansion and Reorganization.”

29 Office of the U.S. Secretary of Defense, Annual Report to Congress: Military and Security Developments Involving the People's Republic of China 2019, May 2, 2019,

30 Ben Lowsen, “Is China Abandoning Its No First Use Nuclear Policy?” Diplomat, March 21, 2018,

31 Eric Heginbotham, et al., Domestic Factors Could Accelerate the Evolution of China’s Nuclear Posture (Santa Monica: RAND Corporation, 2017),

32 Office of the U.S. Secretary of Defense, Annual Report to Congress: Military and Security Developments Involving the People’s Republic of China 2018.

33 Thomas Shugart, “Has China Been Practicing Preemptive Missile Strikes Against U.S. Bases?” War on Rocks, February 6, 2017,

34 Jesse Johnson, “The U.S. Wants Japan’s Help to Close Its Missile Gap With China,” Japan Times, August 25, 2019,

35 James Goldrick, “China’s Intelligence Gathering at Sea: Some Implications,” Lowy Institute, July 24, 2017,

36 Park Hui-seok, “[Dandog] jinan 3 nyeongan oegug gunham-ui uli suyeog chimbeom hoes-suneun 602 hoe ... 505 hoega jung-gug gunham sohaeng,” [Foreign warship’s violations of our waters amounts to 602 times in the last three years], Daily Chosun, March 6, 2019,

37 Park Chang-kwon, “jung-gug-ui seohae mich KADIZ nae gunsahwaldong jeung-gaga juneun sisajeom” [Implications of China’s growing military activities in the Yellow Sea and KADIZ], Korea Institute for Maritime Strategy Periscope 147, January 11, 2019,

38 Kristin Huang, “China Flexes Its Military Might With Series of Naval Exercises in Local Waters,” South China Morning Post, August 13, 2018,

39 Bryan Lynn, “China Launches New Intelligence Gathering Ship,” Voice of America, January 12, 2017,; and Yoo Yong-won, “Jagi apmadangcheoleom… jung-gunham 3cheog tto donghae jin-ib” [3 Chinese Warships Enter the East Sea as if It’s Their Own Front Yard], Chosun Ilbo, February 27, 2019,

40 Jo He-rim, “KADIZ Emerges as Potential Flashpoint?” Korea Herald, July 24, 2019,