[العمل المشترك الكوري-الياباني حول العالم 2050] ② البيئات العسكرية والأمنية المستقبلية حتى عام 2050: تحديات وفرص للعلاقات الكورية-اليابانية

Source: (Kristensen et al. 2024).

China’s growing nuclear capabilities enable the PLA to target more U.S. cities, military facilities, and leadership sites, marking a shift from a minimal deterrence strategy focused on MAD to one capable of inflicting greater damage in a nuclear exchange. This modernization includes the development of advanced delivery systerns to counter U.S. missile defenses and lower-yield weapons for more discriminate strikes, suggesting that Beijing aims to sustain multiple rounds of counterstrikes and increase its ability to dominate in a nuclear conflict. These advancements highlight China’s long-term commitment to achieving a “world-class” military by 2049.

China’s nuclear strategy emphasizes deterrence against a first strike and counterstrike capabilities to retaliate against an adversary’s military, population, and economy, aiming to de-escalate conflicts and return to conventional warfare while maintaining sufficient force to deter further aggression. Although Beijing upholds a no-first-use (NFU) policy, ambiguities exist, as the PRC may consider nuclear first use in response to non-nuclear threats endangering its nuclear forces, command and control (C2), or the survival of the CCP regime, particularly in scenarios involving Taiwan. The combination of conventional and nuclear missile forces and the dispersal of mobile systerns during conflicts complicate the identification of missile types and escalation management, increasing the risk of inadvertent attacks on nuclear assets and “use-or-lose” pressures. This strategic ambiguity remains a key challenge for adversaries attempting to navigate deterrence and escalation dynamics with the PRC (Kristensen et al. 2024, 101–102).

China’s nuclear forces, when developed to achieve parity or near parity with the United States, could enable China to adopt a more assertive gray zone strategy. To date, China has adhered to a minimum deterrence strategy aimed at countering potential U.S. aggression. However, as U.S.-China military competition accelerates and China’s gray zone strategies become increasingly aggressive, its nuclear forces are expected to play a more significant role. In a scenario of military conflict between China and the U.S. and Taiwan over Taiwan, China may utilize its nuclear strategies in various ways.

Currently, China’s comparatively weaker nuclear forces make it wary of escalation in gray zone disputes, fearing they may lead to full-scale conventional warfare and potentially nuclear conflict with the U.S., where China’s nuclear capabilities remain inadequate. However, in a decade or more, when nuclear parity or mutual assured destruction is achieved, China may feel less compelled to exercise restraint in gray zone strategies.

China has already demonstrated the use of complex strategies in gray zone conflicts, and if nuclear capabilities are incorporated, it is likely to adopt even more assertive approaches. This could lead to an expansion of China’s aggression in areas such as the South China Sea, East China Sea, and Taiwan, posing significant security threats to South Korea and Japan.

2. Multipolar Nuclear Strategic Environment in Northeast Asia

The challenges to strategic stability in a multipolar world are becoming increasingly evident as the erosion of US-Russia arms control frameworks, exemplified by the suspension of New START, highlights the fragile nature of bilateral agreements. The shift toward a multipolar nuclear order, with China’s growing arsenal and its potential role in a broader arms race, complicates efforts to maintain stability. Meanwhile, Russia’s actions in Ukraine, including its misuse of nuclear deterrence, expose the limitations of existing arms control and nonproliferation agreements in addressing modern geopolitical crises. These developments raise concerns about the adaptability of traditional strategic stability concepts to a multipolar environment, where technological advancements and the integration of emerging nuclear powers demand new approaches (Kühn 2023).

As the post-Cold War order concludes, great power geopolitical competition intensifies, with the emergence of what could be termed “the axis of revisionism.” This includes the ongoing Ukraine war, closer strategic ties between China and Russia, the military alliance between North Korea and Russia formalized in June 2024, and Iran’s military support to Russia’s Ukraine war through drone supplies. Well-documented missile cooperation between North Korea and Iran further adds to these dynamics. Together, military cooperation among North Korea, China, and Russia is likely to have profound implications for Northeast Asian geopolitics.

While the bilateral nuclear balance between the U.S. and Russia has been pivotal, the emerging era will prioritize a multipolar nuclear order. Strategic agreements between the U.S. and Russia may not be extended, and the likelihood of nuclear arms negotiations between the U.S. and China remains extremely low. Meanwhile, North Korea continues to enhance its nuclear and missile capabilities despite international sanctions. The strategic cooperation among North Korea, Russia, and China is accelerating in this context (Eom 2024).

Although a formal trilateral alliance has not yet emerged, strategic contradictions and overlaps exist among these nations’ interests. Nonetheless, their common opposition to the U.S. could drive closer collaboration, particularly if the U.S.’s relative military strength declines. If Russia utilizes nuclear power to alter the status quo in Europe, China and North Korea may similarly combine their nuclear capabilities to seek changes in Northeast Asia. Such developments would compel the U.S., South Korea, and Japan to address a multifaceted nuclear threat.

In such a scenario, challenges arise over how the U.S. could extend nuclear deterrence to South Korea and Japan, and how the region could collectively respond to a hybrid nuclear threat posed by North Korea. Conversely, international and multilateral cooperation to address these developments remains limited.

V. Prospects for South Korea-Japan Security Cooperation Toward 2050

Long-term security cooperation between South Korea and Japan becomes increasingly critical. First, if the U.S. East Asia security strategy undergoes fundamental shifts, both nations could face heightened security threats. Since World War II, South Korea and Japan have relied on close alliances with the U.S. to ensure their security. During the Cold War, their strategy was centered on countering the military threats from communist forces, with the U.S. alliance serving as the axis of this framework. As Victor Cha has noted, when U.S. security commitments to East Asia weaken, South Korea and Japan have historically accelerated security cooperation despite bilateral tensions (Cha 1999). While this trend has not always been consistent, a weakening U.S. security commitment underscores the growing necessity for South Korea-Japan security collaboration. If U.S. foreign policy shifts further toward Trumpian “America First” doctrines or offshore balancing strategies, the security needs of South Korea and Japan will inevitably increase. Managing bilateral issues effectively while establishing new frameworks for security cooperation will be crucial.

Second, as U.S.-China strategic competition intensifies, South Korea and Japan will face similar security challenges. The U.S. may leverage the South Korea-U.S. and U.S.-Japan alliances to counter China’s security threats, requiring both countries to increase defense spending and adapt their strategic frameworks. This burden is heavier for South Korea. Japan already maintains direct military tensions with China, particularly in the East China Sea, and has been proactively pursuing changes in the U.S.-Japan alliance to counter China’s military rise. In contrast, South Korea has yet to formulate clear strategic responses, despite the Taiwan Strait crisis posing a significant threat to its supply chains and economic security.

In the long term, if China secures dominance in the first island chain and integrates regions within the Belt and Road Initiative into its security sphere, South Korea and Japan will face shared exposure to China’s threats. As U.S.-China competition escalates into military confrontation, and as Taiwan Strait and South China Sea issues impact the protection of supply routes, economic security, and military security in South Korea and Japan, the need for cooperation will only intensify.

South Korea and Japan also face the challenge of balancing their deep economic ties with China while addressing U.S. demands for military containment of Beijing. The broad areas of cooperation under frameworks such as China-South Korea-Japan trilateral initiatives further complicate strategic responses to U.S.-China competition for both countries.

Third, amid the rapid advancement of cutting-edge technology, South Korea-Japan technological cooperation is increasingly vital. On the one hand, both countries must prevent the military exploitation of advanced technologies that could destabilize strategic stability in East Asia. As liberal democracies, they should collaborate to establish international norms to prevent the militarization of AI and other emerging technologies.

At the same time, they must prepare for great power geopolitical competition leveraging advanced technologies. China’s potential to surpass the U.S. in military AI and quantum technology could rapidly shift the military balance. Despite changes in the U.S. global strategy, technological cooperation among the U.S., South Korea, and Japan remains indispensable. Even with lukewarm U.S. engagement, sustained South Korea-Japan cooperation in advanced technology is crucial. This necessitates close dialogues to evaluate security environments and align security strategies between the two nations.

Fourth, the issue of the future global nuclear order is directly linked to the security interests of South Korea and Japan. If the U.S. extended deterrence commitment weakens while nuclear capabilities of China, North Korea, and Russia grow, coupled with strengthened cooperation among these states, it would pose a critical threat to the security of both South Korea and Japan. Therefore, it is important to identify areas where South Korea and Japan can cooperate to address challenges.

First, South Korea and Japan need a shared understanding of the weakening and possible collapse of the global nuclear order. As non-nuclear weapon states surrounded by nuclear-armed nations, South Korea and Japan share a common predicament. Thus, they should strongly advocate for the strict adherence to the Nuclear Non-Proliferation Treaty (NPT), the suppression of vertical nuclear proliferation among major powers, and the necessity of arms control negotiations among nuclear-armed states. In this process, efforts should also be made to establish a multilateral framework that addresses the complete denuclearization of North Korea. Additionally, it is crucial to recognize that the nuclear order in Northeast Asia carries significant global implications and to devise joint measures to address this issue on a global scale.

Second, though immediate prospects for nuclear arms control agreements between the U.S. and China are limited, the importance of dialogue and laying the groundwork for future negotiations must be underscored. South Korea and Japan, as key U.S. allies, should actively support U.S.-led efforts to initiate crisis management discussions with China, emphasizing the need for transparency and responsible nuclear strategy. Both nations must strengthen regional coordination with the U.S. to ensure unified messaging while enhancing their own deterrence capabilities, particularly in missile defense, to complement U.S. efforts and maintain regional stability. Furthermore, they should advocate for China’s inclusion in multilateral arms control frameworks, such as through the P5 or regional security mechanisms, encouraging broader engagement and accountability. By aligning closely with U.S. strategies and promoting multilateral dialogue, South Korea and Japan can contribute to reducing risks and ensuring stability amidst increasing U.S.-China strategic competition (Santoro 2023).

Third, given the growing nuclear threats, joint efforts between South Korea and Japan are necessary to strengthen the U.S. extended deterrence commitment. Although South Korea and Japan maintain bilateral alliances with the United States, they face common challenges due to nuclear threats from neighboring countries. The Camp David Agreement includes provisions for immediate consultations in the event of issues significantly affecting regional security. Similarly, close cooperation among South Korea, Japan, and the United States is essential when nuclear threats from neighboring countries escalate. The core of this effort lies in the U.S. extended deterrence commitment, and it will require a shared understanding between South Korea and Japan as well as coordinated demands on the United States to continuously enhance this commitment.

Fourth, if North Korea’s nuclear threat intensifies and the U.S. extended deterrence weakens, South Korea may feel an increasing necessity for independent nuclear armament. In such a scenario, South Korea would inevitably face concerns about economic sanctions from the United States and the international community, as well as fears of a nuclear domino effect involving Japan and potentially Taiwan. If South Korea finds no alternative to independent nuclear armament, it will need to work closely with Japan in advance to establish mechanisms to convince Japan that South Korea’s nuclear armament contributes to Japanese security and regional nuclear deterrence in Northeast Asia. Exploring the feasibility of prior consultations or dialogues between South Korea and Japan will be crucial to prevent South Korea’s nuclear armament from undermining the global nuclear order.

Lastly, both South Korea and Japan need a common preparation for the scenario where nuclear parity is achieved between China and the United States, accompanied by mutual assured destruction. As aforementioned, if China attains nuclear parity with the United States, it is likely to adopt more aggressive gray zone strategies in conflict zones across East Asia. This would pose shared threats to South Korea and Japan, necessitating the sharing of threat perceptions and coordinated responses. Both countries should demand greater transparency from China and effectively convey their shared intent to both the United States and China to encourage nuclear arms control negotiations between the two powers.

Despite existing differences and perception gaps between South Korea and Japan on various issues and within security contexts, they will ultimately face common military threats and the necessity for long-term cooperation. Thus, sustaining multidimensional consultative efforts from now is vital to fostering long-term cooperation.

References

References

Ahn, Kyungmo. 2024. “The New Cold War and the North Korea-China-Russia Triangle: Strategic Implications.” Global North Korea (EAI) Special Report, December 20.

Cha, Victor D. 1999. Alignment Despite Antagonism: The United States-Korea-Japan Security Triangle. Stanford, CA: Stanford University Press.

Chun, Chaesung. 2024. “Military Challenge ②: The Development of AI-Based Autonomous Weapon systerns, Cognitive Warfare, and Changes in the Military Security Order.” EAI National Security Research Center Special Report, September 6.

Eom, Gu Ho. 2024. “The DPRK-Russia-China Triangle Under Trump 2.0: Future Prospects and Strategic Responses.” Global North Korea (EAI) Special Report, December 13.

Jun, Jaewoo. 2024. “China’s Calculus on DPRK-Russia Alignment: A Geopolitical Perspective.” Global North Korea (EAI) Special Report, December 13.

Kristensen, Hans. 2024. “The 2024 DOD China Military Power Report.” Federation of American Scientists, December 18.

Kristensen, Hans M., Matt Korda, Eliana Johns, and Mackenzie Knight. 2024. “Chinese Nuclear Weapons, 2024.” Bulletin of the Atomic Scientists 80, 1: 49–72, 101–102.

Kühn, Ulrich. 2023. “Strategic Stability in the 21st Century: An Introduction.” Journal for Peace and Nuclear Disarmament 6, 1: 1–8.

Office of the Secretary of Defense. 2022. Military and Security Developments Involving the People’s Republic of China: Annual Report to Congress Pursuant to the National Defense Authorization Act for Fiscal Year 2000. Washington, DC: Department of Defense.

Santoro, David. 2023. “Getting Past No: Developing a Nuclear Arms Control Relationship with China.” Journal for Peace and Nuclear Disarmament 6, 1: 68–86.

■ Chaesung Chun is Chair of EAI’s National Security Research Center and Professor at Seoul National University.

■ Translated and edited by Chaerin Kim, Research Assistant
    For inquiries: 02 2277 1683 (ext. 208) | crkim@eai.or.kr