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The significance of the Ninth Congress of the Workers’ Party of Korea can be understood in two principal respects. First, the congress reaffirmed the broad outlines of North Korea’s long-term grand strategy, namely the institutionalization of a permanent relationship of hostile coexistence between North and South Korea, a strategic orientation first articulated during the Eighth Party Congress period. Second, compared with the Eighth Congress period, North Korea’s capabilities and institutional arrangements for implementing this long-term strategy have become more stable and consolidated. On this basis, the Ninth Congress set out policy priorities for the next five years.

This article analyzes five macro-structural developments that form the background to the convening of the Ninth Party Congress. First, North Korea’s worldview of international politics is grounded in what may be characterized as hard structural realism. Second, the strategic meaning of nuclear capability has evolved from a security instrument into a central component of regime identity. Third, the advancement of North Korea’s nuclear capabilities structurally generates conditions for long-term hostile coexistence between the two Koreas. Fourth, the articulation of the “two hostile states” doctrine represents an attempt to prevent the domestic political vulnerabilities that North Korea faces as the inter-Korean power gap continues to widen. Fifth, for the foreseeable future, inter-Korean relations are likely to be characterized by permanent hostile coexistence grounded in a highly militarized deterrence equilibrium, fragile crisis stability, and intense North Korean hostility toward South Korea.

A Hard Structural Realist Worldview

Since 2017, the expansion of North Korea’s nuclear capabilities has reinforced a worldview that closely resembles hard structural realism. This perspective includes the following perceptions: the international system is fundamentally dangerous; strong states dominate weak states, and survival is ensured not through trust or agreements but through power; if a state possesses sufficient power, adversaries are compelled to respect it; if it appears vulnerable, however, it invites pressure or attack; from this standpoint, international politics is not governed by reliable commitments but by the distribution of coercive capabilities.

After declaring the completion of its national nuclear forces in 2017, North Korea came to believe that its security could be guaranteed independently, without reliance on the promises or commitments of other states. The diplomatic engagements of 2018–2019, including summit diplomacy with the United States, China, Russia, and South Korea, were made possible in part because the regime believed that its nuclear capability had secured its strategic position.

Several strategic principles follow from this worldview. First, nuclear weapons must never be abandoned. They may be relinquished only when the entire hostile environment surrounding North Korea disappears. In this sense, nuclear weapons function as a permanent strategic insurance policy. Second, diplomacy is pursued instrumentally. Negotiations are undertaken primarily to obtain short-term advantages rather than to transform fundamentally hostile relationships. Agreements with great powers, in particular, are not regarded as reliable. Third, North Korea seeks to demonstrate its willingness to strike first if necessary. Such signaling is intended to deter adversaries preemptively by raising the perceived risks of hostile military action. Fourth, internal political unity must be preserved. Because the external environment is perceived as fundamentally hostile, internal divisions that might weaken the state must be prevented. Information control, ideological mobilization, and the construction of external threats serve this purpose. Finally, North Korea assumes that hostile relationships with its adversaries will persist for decades. Accordingly, the state must organize long-term military planning, invest in strategic technologies, and structure party-state institutions around national defense. Rather than expecting reconciliation on the Korean Peninsula in the near future, the regime prepares for a prolonged period of confrontation and uneasy coexistence.

The Transformation of Nuclear Capability: From Security Instrument to Regime Identity

In the early stages of North Korea’s nuclear development, nuclear weapons functioned primarily as instruments for protecting the regime. The regime existed prior to nuclear weapons, and nuclear capability was acquired as a tool for safeguarding it.

Over time, however, the nuclear program became deeply embedded within the state. The development of nuclear weapons required enormous national mobilization. Scientists, engineers, military organizations, industrial sectors, and vast state resources were devoted to the program. As this effort continued for decades, the nuclear program gradually became integrated into the state’s institutional structure. Large bureaucratic organizations emerged to manage nuclear development. Political legitimacy increasingly became associated with the successful acquisition of nuclear weapons. National pride likewise became linked to nuclear strategic capability.

As this process deepened, the relationship between nuclear capability and the regime underwent a qualitative transformation. Nuclear weapons ceased to be merely instruments of security and instead became constitutive elements of the state’s identity and institutional structure. The state began to define itself explicitly as a nuclear state.

Under such conditions, the regime is no longer simply protected by nuclear weapons. Rather, it becomes politically and institutionally organized around nuclear status. National pride, sovereignty, military doctrine, institutional structures, and ideological narratives all become closely intertwined with nuclear capability.

When nuclear weapons function solely as security tools, they remain negotiable. However, when nuclear capability becomes embedded in the state's identity, relinquishing it is perceived as tantamount to transforming the entire political system. Nuclear disarmament then appears as the loss of sovereignty, prestige, strategic security, and political dignity. Even if a leader were to consider nuclear reduction desirable, the institutional interests of domestic organizations and the regime's legitimacy narratives would make such a policy extremely difficult to implement.

North Korea represents an especially strong example of this phenomenon. First, the country endured decades of sanctions and external pressure, yet its nuclear program survived. This experience reinforced the belief that nuclear capability guarantees regime survival. Second, the asymmetry of national power between the two Koreas remains substantial. South Korea possesses far greater economic strength, technological sophistication, and support from alliances. Nuclear weapons help compensate for this imbalance. Third, nuclear achievements function as symbols of political legitimacy, demonstrating successful leadership, national strength, and technological capability. Fourth, nuclear capability has become institutionally embedded throughout the state apparatus. Missile development, nuclear engineering, and strategic weapons command occupy central roles within the political system. These institutions have strong incentives to preserve and expand the nuclear arsenal.

This process of institutionalization accelerated under Kim Jong-un. Several developments illustrate this trend:

• December 2011: Following Kim Jong-il’s death, nuclear development and satellite launches were described as his greatest achievements.

• 2012: Nuclear possession was mentioned in the constitutional preamble.

• 2013: The law on the status of a self-defensive nuclear weapons state was enacted.

• 2017: North Korea declared the completion of its national nuclear forces and introduced the concept of a strategic state.

• 2022: The Nuclear Forces Law codified the irreversibility of nuclear state status and conditions for nuclear use.

• 2023: Constitutional revisions incorporated nuclear policy.

• 2026: The 9th Party Congress declared the irreversible status of North Korea as a nuclear-armed state and credited Kim Jong-un with building “revolutionary armed forces fully prepared for any form of war.”

Enduring Hostile Coexistence: An Inevitable Accompaniment of Nuclear Advancement

One implication of the advancement of North Korea’s nuclear capabilities—symbolized by the 2017 declaration of completed nuclear forces—is that a full-scale war on the Korean Peninsula would necessarily become a nuclear war. Such a war would bring catastrophic consequences for both Koreas. Therefore, both sides will be extremely cautious about initiating a full-scale war.

This situation has produced major changes in North Korea’s security environment. First, regime survival has become more secure. Second, the probability of invasion has become extremely low. Third, military unification has become unrealistic. Fourth, North Korea can independently balance stronger adversaries.

However, certain factors remain unchanged. Military and political conflicts between North and South Korea continue. Militarily, both sides avoid full-scale war because nuclear war would be catastrophic. Yet competition continues below the threshold of total war. The expectation that both sides wish to avoid nuclear catastrophe may even make limited conflicts more likely. Politically, conflicts persist because the underlying sources of hostility remain unresolved. The two Koreas possess profound and irreconcilable differences regarding political systems, alliance structures, ideologies, claims to legitimacy, and historical narratives. Reconciliation therefore remains extremely difficult.

War is too dangerous, yet reconciliation is too difficult. This structural condition makes the inter-Korean adversarial relationship effectively permanent. Both sides must therefore prepare to manage a rivalry that may last indefinitely. Inter-Korean relations have settled into a pattern of long-term hostile coexistence.

The Doctrine of Two Hostile States: Compensating for the widening inter-Korean divergence

The advancement of North Korea’s nuclear capability removes the risk of invasion but does not eliminate political hostility between the two Koreas. Consequently, it structurally produces long-term hostile coexistence.

The doctrine of two hostile states represents a further step. Even before 2017, structural hostility existed between North and South Korea, yet negotiations and engagement were still possible.

After securing nuclear deterrence, North Korea introduced the two hostile states doctrine in order to prevent the structural political hostility between the two Koreas—mediated through the widening inter-Korean gap—from amplifying disadvantages for North Korea.

Following the 9th Plenum of the 8th Central Committee in December 2023, North Korea officially designated South Korea as the most hostile foreign state.

While nuclear deterrence eliminates the possibility of absorption through military means, North Korea still remains inferior to South Korea in most non-military domains. The regime sees no realistic prospect of overcoming this disparity.

The hostile two-state doctrine, therefore, aims to eliminate domestic political vulnerabilities arising from South Korea’s growing superiority by intensifying hostility and enforcing complete separation. Rather than pursuing unification, which it now considers impossible, North Korea seeks long-term coexistence based on hostility.

However, North Korea’s doctrine of the two hostile states does not end with a one-time declaration of hostility toward South Korea. Rather, it creates a structural requirement to continuously reproduce and reaffirm antagonism between the two Koreas. North Korea’s policy of permanently maintaining its nuclear deterrent structurally generates international sanctions and diplomatic isolation, which in turn virtually guarantees that the gap between North and South Korea will continue to widen in the future.

In other words, the strategy of long-term hostile coexistence toward South Korea, grounded in nuclear capability, is a strategic line that structurally perpetuates the internal political vulnerabilities of North Korea arising from the expanding inter-Korean disparity. The articulation of the two hostile states doctrine, therefore, reveals North Korea’s intention to compensate for the structural intensification of these internal vulnerabilities by strengthening hostility toward South Korea.

Under the strategy of long-term hostile coexistence with the South, domestic political stability in North Korea presupposes the maintenance of an intense antagonism toward South Korea. Yet sustaining such a high level of hostility over a long period is not easy. To make this possible, North Korea must maintain a high degree of information control, external isolation, and internal political discipline. It may also become necessary to periodically provoke military crises with South Korea or to exaggerate the dangers of South Korean infiltration and subversion inside North Korea.

Only through such measures can the regime, to some extent, prevent the de-charismatization or routinization of intense hostility toward South Korea. Even so, maintaining a high level of anti-South Korean hostility—especially among the younger generation in North Korea—will remain a difficult challenge.

Conclusion and Implications

After acquiring nuclear capability, North Korea’s security structure has fundamentally changed. The regime is responding to the new strategic environment through a dual strategy: first, strengthening and permanently institutionalizing nuclear deterrence, and second, permanently intensifying hostility toward South Korea. The 9th Party Congress reconfirmed this strategic orientation, reviewed past achievements, and presented goals for the next phase.

The implications for future inter-Korean relations can be summarized as follows. First, because of mutual nuclear deterrence between the United States–South Korea alliance and North Korea, the probability of full-scale war is very low. Second, crisis stability is weak. North Korea’s heightened hostility toward South Korea, the breakdown of dialogue, high levels of military readiness on both sides, North Korea’s tactical nuclear strike capabilities, and reciprocal preparations for preemptive strikes all increase the risk that crises could escalate rapidly. Third, North Korea is likely to continue improving its military capabilities and periodically provoke South Korea in order to prevent its deterrence from being weakened by U.S.-South Korean technological advances and to sustain hostility toward the South. Fourth, North Korea’s strategy of permanently maintaining nuclear deterrence is likely to endure, and with it the doctrine of two hostile states. Fifth, future inter-Korean relations will remain characterized by hostile coexistence based on a highly militarized deterrence equilibrium. Peace may persist, but it will be a form of hostile peace, grounded in heavy military buildup, fragile crisis stability, and enduring hostility. ■ 

■ Hyeong Jung PARK is an Independent Researcher on North Korea.

■ Edited by Sangjun LEE, EAI Research Associate; Inhwan OH, EAI Senior Research Fellow
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