On October 18, South Korea’s National Intelligence Service (NIS) announced that North Korea had decided to send four brigades of 12,000 troops, including special forces, to the war in Ukraine and had already begun deployment. The United States remains cautious about these reports, while Russia has denied the dispatch of North Korean troops. However, Ukraine’s military intelligence (HUR) predicts that North Korean forces will be sent to Russia’s western Kursk region and will be ‘ready to fight’ by around November 1.

It is noteworthy that North Korea’s deployment to Russia coincides with heightened tensions on the Korean Peninsula, with Pyongyang making provocative claims that South Korea’s drones have infiltrated its airspace. On October 15, North Korea destroyed the northern sections of the inter-Korean roads and railways along the Gyeongui and Donghae lines. This reflects North Korea’s intent to emphasize ‘hostility’ between the two Koreas and reinforce the rhetoric of separation and severance while bolstering its regime’s stability through stronger ties with Russia.

1. The Background and Dilemma of North Korea’s ‘Relationship between two belligerent states’ Doctrine

In a speech at the 9th Enlarged Plenary Meeting of the 8th Central Committee of the Workers’ Party of Korea in December 2023, Kim Jong Un declared, “Inter-Korean relations are no longer those of the same peoples but have become those of two belligerent states or states in a state of combat.” Furthermore, at the 10th Session of the 14th Supreme People’s Assembly in January this year, he argued that North Korea’s constitution should be amended to reflect plans to “completely occupy, recapture, and incorporate South Korea into its territory” in the event of war on the Korean Peninsula. This doctrine reflects a rejection of unification and an abandonment of the concept of a single Korean ethnicity.

At first glance, North Korea’s ‘Relationship between two belligerent states’ doctrine reflects Kim Jong Un’s confidence. Having reached the 12th year of his rule, Kim achieved nuclear armament, which set him apart from his predecessors, and is likely convinced that no one can challenge his authority. It also reflects his belief that North Korea’s nuclear armament has offset or reversed the power disparity with South Korea, which has persisted since the 1970s, and it has tilted the balance in the inter-Korean relations in its favor: between a ‘nuclear-armed North Korea’ and an ‘inferior middle-power South Korea’.

However, the doctrine may also signal Kim’s underlying anxieties. North Korea faces several challenges, including the cumulative impact of harsh economic sanctions from its nuclear program, the strain on regime stability caused by COVID-19, and the potential discontent and shifting attitudes among its people. Regardless of whether the South Korean government adopts conservative pressure or a more progressive engagement policy, Pyongyang may still fear unwanted political penetration. This may have resulted in its ‘Relationship between two belligerent states’ doctrine as formalizing separation and severance with South Korea deemed necessary.

Theoretically, this ‘Relationship between two belligerent states’ doctrine presents two possible paths. First, if North Korea successfully coerces South Korea with its nuclear weapons, the doctrine could evolve into a ‘cooperative two-state doctrine.’ North Korea may argue that the current hostility is situational and promote this idea within South Korean society that inter-Korean relations could turn cooperative if South Korea abandons its unification efforts based on liberal democracy, accepts North Korea’s agenda (such as U.S.-DPRK nuclear disarmament talks), and weakens the ROK-U.S. alliance.

On the other hand, if the doctrine stems from insecurity, North Korea might emphasize hostility more than two-state relations. In such a scenario, exclusion-focused policies would be more beneficial than coexistence, serving both internal control and regime preservation. Rejecting ethnic unity in favor of general principles of international relations could also help prevent absorption by South Korea, thereby securing North Korea’s autonomy.

The two-state doctrine presents a fundamental logical dilemma. This dilemma makes it difficult for North Korea to maintain both the two-state doctrine and ethnic nationalism as open strategies to buy time. At the core of North Korea’s power structure is the Suryong (supreme leader), a figure central to guiding the working class and the party toward the revolution and construction to victory. From the founding of the regime, Kim Il Sung promoted the slogan “the completion of the revolution on the Korean Peninsula.” However, the two-state doctrine could imply abandoning this revolutionary mission of unification, which would raise doubts about the very legitimacy of the Suryong. Such a shift would be tantamount to denying the foundation of Kim Jong Un’s authority, which is built on the legacy of hereditary succession across three generations.

Moreover, North Korea’s highly mobilized state apparatus has long been justified under the goal of completing the Korean Revolution by strengthening the Republic’s internal revolutionary capacity. If the unification mission were to be abandoned, people in North Korea might begin questioning why they must continue enduring hardship and control in the name of achieving ‘self-reliance.’ Lastly, they might interpret its regime’s emphasis on separation and severance as a reflection of inferiority toward South Korea. As external information spreads and North Koreans become increasingly aware of South Korea’s national strength, the regime’s push for severance risks being seen as an attempt to conceal the reality of North Korea’s regression, despite its claims of being a ‘nuclear power.’

These logical inconsistencies may explain why North Korea did not disclose the full details of the constitutional amendments made during the 10th Session of the 14th Supreme People’s Assembly, held from October 7 to 8 this year. It remains unclear whether the amendments originally included elements of the ‘Relationship between two belligerent states’ doctrine but were not reported or if the changes were hastily introduced in response to the alleged drone incursions and the closure of inter-Korean roads and railways. However, these developments suggest North Korea has yet to overcome the inherent contradictions within the two-state doctrine.

2. Kim Jong Un’s Crisis Mentality, Escalation of Hostility, and Deployment to Russia

It seems that Kim Jong Un believed he needed to quickly choose between the two paths under the ‘Relationship between two belligerent states’ doctrine—either coexistence as two separate states or escalating hostility—to overcome North Korea’s current crisis. In the end, North Korea chose hostility, aiming to sever ties with South Korea, a move that reflects Kim’s growing insecurity.

Leaflets dropped by drones mentioned the luxurious lifestyle enjoyed by Kim Jong Un and Kim Ju Ae despite the poverty and oppressive control experienced by North Korean citizens. However, the leaflets contained relatively fewer direct attacks on the ‘supreme dignity,’ such as issues related to Kim’s family or legitimacy. Whether these leaflets were fabricated by North Korea, carried by drones, or spread by other means, it is likely that the information in them was already circulating within North Korean society.

North Korea’s intense reaction to the drone incident suggests that the leadership is weary that this type of information might foster a certain degree of consensus within its society, which could provoke anger among the people and lead them to harbor resentment toward the regime and system. Therefore, the North Korean leadership, including Kim Jong Un, sought to use the drone incident to deliver the following messages:

(1) There are malicious, hostile forces systematically trying to undermine North Korea’s socialist system.

(2) The content being spread is distorted and intended to sow discord between the leadership and the people, and believing or being swayed by it is tantamount to supporting a   conspiracy to collapse the regime.

(3) The recent inflow of foreign information and culture is not accidental but a deliberate effort by impure external forces, and thus, it must not be trusted or allowed to sway people.

In line with this message, North Korea physically severed the inter-Korean Gyeongui and Donghae rail lines, symbolically demonstrating that the separation between the two Koreas is permanent and will not be restored.

While the deployment of North Korean troops to Russia might appear as an isolated measure, it is closely tied to recent developments. By deploying troops, North Korea can demonstrate to both domestic and international audiences that the Comprehensive Strategic Partnership Treaty signed in June between North Korea and Russia is no longer symbolic but a genuine alliance. This sends a message that North Korea has secured a reliable partner against its ‘hostile state’, South Korea, highlighting the seriousness with which the North Korean leadership views South Korea’s confrontational actions. It also encourages North Koreans to expect economic benefits from closer cooperation with Russia.

Given that sending workers to Russia has long been a vital source of foreign currency for North Korea’s economy, deploying over 10,000 troops suggests even greater economic returns than past labor exports. Moreover, as Western observers fear, this deployment could give North Korea access to Russian technology, such as ICBMs or nuclear submarine systems. Even without direct military aid, Russia could still provide critical support—such as military reconnaissance satellites—that could be applied to advancing North Korea’s nuclear and missile programs.

In the medium term, the deepening of DPRK-Russia ties and the evolution of their relationship into an alliance suggest that Russia may come to view North Korea’s nuclear development not as a problem to be solved but as something it can condone. This could pave the way for a ‘nuclear alliance’ between the two countries. Such an alliance would allow both North Korea and Russia to increase their leverage against the United States. For North Korea, this could mean utilizing the ‘nuclear shadow’ more proactively to provoke and threaten South Korea.

3. Outlook on North Korea’s Future Actions and South Korea’s Response

North Korea’s efforts to fuel hostility toward South Korea and its troop deployment to the Ukraine war are closely tied to its attempt to escape the ‘Relationship between two belligerent states’ dilemma. For the time being, Pyongyang will likely continue escalating tensions on the Korean Peninsula. Rather than engaging in provocations that could lead to full-scale war, North Korea is expected to focus on low-to-moderate-intensity provocations to maximize the impact of heightened tensions with South Korea.

North Korea may use drone incidents as a pretext to fire automatic cannons or anti-aircraft artillery at the Demilitarized Zone (DMZ), Guard Posts (GP), or along the Military Demarcation Line (MDL). At sea, it could cross the south of the Northern Limit Line (NLL), conduct coastal artillery fire, or attempt to seize South Korean fishing vessels. Additionally, North Korea might provoke South Korea domestically through actions such as shooting at one or two South Korean personnel or targeting certain GP assets, complicating South Korea’s ability to respond immediately. Pyongyang could also conduct large-scale artillery drills north of the MDL or launch short-range ballistic missiles to create the impression of military superiority over South Korea.

Therefore, South Korea must demonstrate firm response capabilities and readiness through joint ROK-U.S. exercises to ease domestic anxiety about North Korea’s provocations. At the same time, it must reaffirm its commitment to bringing diverse information into North Korea and maintaining communication with North Korean citizens. In line with the inter-Korean dialogue and cooperation framework outlined in the “8.15 Unification Doctrine,” South Korea should call for talks to prevent accidental clashes between the two Koreas.

Moreover, in coordination with the international community, South Korea should highlight the illegitimacy of North Korea’s troop deployment to Russia. If concrete evidence confirms that North Korea has deployed troops to the Ukraine war, South Korea must be ready to take new steps, including providing weapons and ammunition to Ukraine—a measure previously avoided.

Most importantly, South Korea must urge the United States to reinforce its extended deterrence commitments by strongly emphasizing the risk that the deepening DPRK-Russia alignment could evolve into a nuclear alliance in the medium term. Although the outcome of the U.S. presidential election in November could influence individual administration policies, countering North Korea and Russia’s nuclear threats is a shared interest for South Korea and the United States. Therefore, South Korea should push for significantly stronger extended deterrence measures far beyond the Washington Declaration, including the redeployment of U.S. tactical nuclear weapons to the Korean Peninsula or U.S. support for strengthening South Korea’s indigenous nuclear capabilities, even if South Korea has to bear the related costs and burdens.