Analysis of North Korea's Enhanced Tactical Nuclear Doctrine and the Risk of an Expanding Regional Arms Race

Executive Summary

This situation is not the result of a single stimulus, such as the discussion of a new nuclear strategy at the U.S. Department of Defense. Rather, it is the simultaneous expression of North Korea's doctrine of preemptive tactical nuclear use, established since the 8th Party Congress in 2021, converging with three triggers: ROK-U.S. military exercises, South Korea's acquisition of nuclear-powered submarines, and discussions in Japan on revising its Three Non-Nuclear Principles. North Korea is employing a dual structure, distinguishing between anonymous commentaries and official Foreign Ministry statements to keep channels with the U.S. open while maintaining a hardline stance on ROK-U.S. military cooperation. With China intervening by labeling Japan's defense budget increase as "neo-militarism" and North Korea reprinting these statements to join the pressure campaign against Japan, the North Korean nuclear issue is transforming into a subordinate variable within the broader U.S.-China competition. Over the next 6-12 months, it is most likely that the situation will remain in a conventional management phase, depending on three variables: the level of military demonstrations after the Ulchi Freedom Shield (UFS) exercises, whether the new U.S. nuclear strategy is formalized, and the pace of political progress on discussions in Japan regarding its Three Non-Nuclear Principles. South Korea needs a phased response that separates its response tracks for the new U.S. nuclear strategy and the ROK-U.S. exercises, bifurcates its explanation of the nuclear submarine program by addressing the security logic and non-proliferation obligations separately, and tracks potential policy changes in Japan as a separate indicator.

I. Situational Analysis

North Korea's Reaction to the New U.S. Nuclear Strategy and Its Enhanced Tactical Nuclear Doctrine: A Situational Analysis

1. Background and Developments

The recent situation was triggered by internal discussions at the U.S. Department of Defense about a new nuclear strategy. However, to understand Pyongyang's pattern of response, one must first examine the series of statements issued since early August 2026. On August 12, First Vice Minister of Foreign Affairs Jang Kum Chol described South Korea's "Jangbogo-N" nuclear-powered submarine acquisition plan as "a new risk factor for the security of the Asia-Pacific region" [2][4]. North Korea warned that the project could trigger a regional "nuclear domino effect" if realized [4]. Two days later, on August 14, a military commentary criticizing the new U.S. nuclear strategy was published simultaneously in the Korean Central News Agency (KCNA) and Rodong Sinmun [2]. On the same day, a spokesperson for the Ministry of Foreign Affairs issued a separate statement targeting the Ulchi Freedom Shield (UFS) exercise, which was set to begin on August 17 [2][19].

This trend is an extension of the doctrine of preemptive use of tactical nuclear weapons established since the 8th Party Congress in 2021 [2]. Since that time, North Korea has been refining its doctrine to expand the role of its nuclear forces from strategic deterrence to operational and tactical denial deterrence [12]. There are also assessments that amid the U.S.-China geopolitical competition, the nature of the North Korean nuclear issue itself has shifted from a WMD non-proliferation issue to a component of a great-power chess game [8]. This doctrine, combined with the Kim Jong Un regime's sense of being under siege, is the product of a structurally reproduced pattern of external messaging, not a one-off statement [2][10].

2. Current Situation

On August 20, the North Korean military launched short-range ballistic missiles into the East Sea [14][18]. The U.S. military acknowledged the launch and reaffirmed its defense commitment to its allies [14]. Through a Rodong Sinmun commentary that described the UFS exercise as "a foolish gamble that invites disaster," the Korean Central News Agency also took aim at discussions in Japan on revising its Three Non-Nuclear Principles [7]. Noteworthy is the passage that directly quoted Defense Minister Koizumi's remark that "we must discuss nuclear-related policies without hesitation," labeling it "an extremely provocative and dangerous remark" [7].

A spokesperson for the Ministry of Foreign Affairs described UFS as "a new level of threat" and stated that North Korea would counter it with "a new level of deterrence" [1][19]. There is a clear difference in tone between the commentary under the anonymous byline of the 'Military Commentary Board' and the official statement from the Foreign Ministry spokesperson [2]. This is a dual structure: leaving room for maneuver on the new U.S. nuclear strategy through a commentary, while reaffirming principles on ROK-U.S. exercises under the Foreign Ministry's name [2]. This can be read as a calculated division of labor intended to keep channels with the United States from closing completely while maintaining a hardline stance on ROK-U.S. military cooperation [2].

China's Ministry of National Defense also intervened in this situation. China described Japan's defense budget request for fiscal year 2027, which reached a record high, as "neo-militarism" and demanded a halt to its remilitarization [13][17]. North Korean media reprinted these Chinese remarks verbatim, demonstrating that it was joining the pressure campaign against Japan [13][17]. In its 2026 yearbook, the Stockholm International Peace Research Institute (SIPRI) assessed that a trend of countries re-emphasizing nuclear weapons as instruments of national power is spreading [3][6]. This, it noted, is a phenomenon occurring amid rising risks of miscalculation and escalation [3].

3. Analysis of Key Actors

North Koreais employing a dual-track strategy. It uses the 'Military Commentary Board' byline to create a buffer on the new U.S. nuclear strategy, while laying down a principled response to the ROK-U.S. joint exercises through official Foreign Ministry statements [2]. From the Kim Jong Un regime's perspective, strengthening its nuclear forces involves three intertwined objectives: diplomatic leverage, military deterrence, and internal regime cohesion [12]. Minister of National Defense Ahn Gyu-baek, while estimating North Korea's nuclear arsenal at 80-120 weapons, qualified this as an estimate from a domestic research institute and reaffirmed the position that North Korea cannot be officially recognized as a nuclear-weapon state [16].

South Koreais pursuing the Jangbogo-N nuclear-powered submarine project based on a security rationale, facing criticism from North Korea regarding proliferation [4][16]. The Ministry of National Defense projects that North Korea's deployment of new multiple rocket launchers and self-propelled artillery in border areas and its 'border fortification' construction will be completed around 2028 [9].

United StatesPresident Trump previously ordered a reduction in the scale of ROK-U.S. joint military exercises, triggering concerns within the allied nation [11]. Trump described North Korea as "not threatening and was respectful," suggesting the reduction in exercise participation was a form of signaling management toward North Korea [11]. Separate from concerns in South Korea about a security vacuum, this also aligns with Trump's personal calculation of keeping open the possibility of resuming U.S.-North Korea summits [18].

JapanThe Ministry of Defense has requested a record-high defense budget for fiscal year 2027 [13], and Defense Minister Koizumi has suggested the possibility of public discussion on nuclear policy [7]. This is leading to discussions on revising the Three Non-Nuclear Principles, drawing checks from both North Korea and China simultaneously [7][13].

Chinais focused on checking Japan's defense budget increase and remilitarization moves [13][17]. Its approach is more focused on managing Japan's military rise within the geopolitical competition framework than on the North Korean nuclear issue itself [13].

4. Key Issues

First, the key question is whether North Korea's dual-messaging structure will lead to an actual policy divergence. Whether the commentaries by the Military Commentary Board will remain mere buffering rhetoric or converge toward the hardline measures seen in the Foreign Ministry statements depends on the intensity of the UFS exercises and the timing of the formalization of the U.S. Nuclear Posture Review [2].

Second is the clash between South Korea's nuclear-powered submarine program and the "nuclear domino" frame promoted by North Korea. While North Korea frames this as a threat to the non-proliferation regime [4], the South Korean government bears the burden of having to technically separate its explanations of security needs from its non-proliferation obligations [2].

Third, the discussion in Japan on revising its Three Non-Nuclear Principles is stimulating the regional nuclear discourse itself by provoking backlash from both North Korea and China [7][13]. The trend pointed out by SIPRI of nuclear weapons being re-emphasized as instruments of national power, coupled with these regional dynamics, has the potential to increase proliferation pressures [3].

Fourth is the issue of consistency in U.S. policy toward the Korean Peninsula. The gap between Trump's order to scale down exercises and the U.S. military's reaffirmation of its defense commitment [11][14] is a factor that sustains the debate within South Korea over the credibility of the alliance.

II. In-Depth Analysis

North Korea's Reaction to the New U.S. Nuclear Strategy and Its Enhanced Tactical Nuclear Doctrine: An In-Depth Analysis

1. Analysis of Root Causes

Viewing this situation as a mere diplomatic rhetorical battle misses the essence of the issue. The root cause lies in the doctrine of preemptive use of tactical nuclear weapons established at the 8th Party Congress in 2021 [2]. From this point, North Korea redesigned the purpose of its nuclear forces to expand from strategic deterrence to operational and tactical denial deterrence [12]. The simultaneous development of intercontinental ballistic missiles (ICBMs) to strike the U.S. mainland and tactical nuclear delivery systems for operations on the Korean Peninsula and in the region is also a product of this doctrinal shift [12].

The backdrop to the establishment of this doctrine is the breakdown of the 2019 Hanoi Summit. When the path to sanctions relief through negotiations was blocked in Hanoi, the Kim Jong Un regime revived its identity as a revolutionary state [10]. The perception of being besieged by external forces, the so-called siege mentality, led to radicalization across all domains: ideology, economy, foreign policy, and nuclear strategy [10]. The new U.S. nuclear strategy and ROK-U.S. exercises are merely stimuli processed within this radicalized foreign policy framework. Even if the stimuli disappear, the doctrine itself remains.

Another root cause is the change in the power distribution structure. For 30 years in the post-Cold War era, the North Korean nuclear issue was treated as a problem of a rogue state challenging the liberal world order [8]. However, in the current transition to a multipolar system, the nature of the North Korean nuclear issue has shifted from a matter of WMD non-proliferation norms to a subordinate variable in the U.S.-China geopolitical competition [8]. North Korea's dual structure—leaving room for maneuver on the new U.S. nuclear strategy with an anonymous commentary while reaffirming its principles on ROK-U.S. exercises under the Foreign Ministry's name [2]—is a calculation based on this structural change. The underlying calculation is not about dealing with the United States as a single adversary, but about adjusting its own position within the U.S.-China competitive framework.

2. Structural Context

Security Structure: The advancement of ROK-U.S.-Japan military cooperation is acting as a catalyst, stimulating regional nuclear discourse. North Korea's Ministry of Foreign Affairs has stated that ROK-U.S.-Japan cooperation is "transforming into a new, spiraling nuclear alliance similar to NATO," and that it will "respond to a new level of threat with a new level of deterrence" [1]. Within this logical framework, South Korea's Jangbogo-N nuclear-powered submarine program, discussions of a new U.S. nuclear strategy, and Japan's debate on revising its Three Non-Nuclear Principles are not separate issues but are linked together in a single chain. First Vice Minister Jang Kum Chol's identification of South Korea's submarine program as the trigger for a "nuclear domino effect" [4] and Rodong Sinmun's labeling of Defense Minister Koizumi's remarks on nuclear policy discussions as "an extremely provocative and dangerous remark" [7] are part of the same narrative.

Political Structure: The discussion within Japan on revising the Three Non-Nuclear Principles is intertwined with changes in the domestic political landscape. The timing of the Ministry of Defense's request for a record-high defense budget for fiscal year 2027 coinciding with remarks on nuclear policy discussions [13][15] means this is not merely a security debate but is functioning as a political frame to justify the expansion of the budget and the defense industry. China's intervention, labeling this as "neo-militarism" [13][17], and North Korea's reprinting of these Chinese statements in its own media [13][17], shows a point of convergence in the interests of North Korea and China regarding pressure on Japan.

Economic Structure: North Korea's line of strengthening its nuclear forces is linked internally with a centralized control system based on self-reliance and self-sufficiency [10]. The restoration of the state's monopoly on trade, announced at the 6th Session of the 14th Supreme People's Assembly in February 2026, is one example [10]. The internal logic is also at play that advancing nuclear capabilities resolves the population's security anxieties, creating conditions for them to focus on economic activities [12]. This creates a paradoxical structure where the longer the external sanctions regime lasts, the stronger the domestic justification for advancing nuclear capabilities becomes.

3. Historical Precedents and Comparative Cases

This is not the first time North Korea has used a dual-messaging structure. A similar pattern was observed in early 2025 when it announced its "new line on strengthening nuclear forces." During a visit to the Ministry of National Defence on the 77th anniversary of the founding of the Korean People's Army, Chairman Kim Jong Un mentioned "a new plan to accelerate the strengthening of all deterrent capabilities, including nuclear capabilities" [5]. Pyongyang responded to the port call in Busan of the U.S. Los Angeles-class nuclear-powered submarine USS Alexandria with a statement from a Ministry of National Defence spokesperson, and to the ROK-U.S.-Japan foreign ministers' meeting with a separate statement [5]. This method of differentiating the issuing body and intensity of statements for each issue is being repeated in the current situation [2].

President Trump's pattern of intervention also overlaps with past precedents. In 2026, Trump ordered the Pentagon to scale down ROK-U.S. joint exercises, stating that "it costs a lot of money" [11]. This raised concerns within the allied nation about the consistency of the deterrence posture against North Korea [11]. In the current UFS situation, North Korea's approach of leaving room for maneuver on the new U.S. nuclear strategy while strongly criticizing the exercises themselves [2] is a classic wedge tactic that exploits the gap between negotiation signals from the Trump administration and ROK-U.S. military cooperation. The case where North Korea launched 10 short-range ballistic missiles while the possibility of a Trump-Kim summit in the second half of 2026 was being discussed [18] reaffirms North Korea's unique parallel tactic of simultaneously attempting to create a climate for summit-level dialogue while conducting military demonstrations.

The international trend diagnosed by SIPRI also positions this incident not as an isolated regional issue but as part of a larger trend. The SIPRI 2026 Yearbook assessed that decades of efforts to reduce nuclear weapons are being rolled back as countries re-emphasize nuclear weapons as instruments of national power [3][6]. This indicates that the paradoxical trend of countries increasing their reliance on nuclear weapons amid rising risks of miscalculation and escalation is being replicated in Northeast Asia [3][6].

4. Key Variables Shaping Future Developments

The first variable is the actual intensity of the UFS exercise and whether North Korea adjusts its behavior after its conclusion. Whether the "new level of deterrence" announced by the Ministry of Foreign Affairs remains at the level of conventional military demonstrations or escalates into a substantive provocation will likely depend on the scale of actions taken by the ROK and U.S. during the exercise period [1][19].

The second variable is the timing and content of the formalization of the new U.S. Department of Defense nuclear strategy. The fact that North Korea is modulating its response level on this issue through anonymous commentaries [2] conversely suggests the possibility that its response level will be elevated if the United States formalizes the new nuclear strategy in an official document.

The third variable is the pace of progress in Japan's discussions on revising its Three Non-Nuclear Principles. With the Ministry of Defense's work to revise the three key national security documents scheduled for completion by year-end [15], the perception that new technologies like drones and AI are fundamentally changing the nature of the battlefield is serving as a backdrop for this revision work [15]. If the discussions on the Three Non-Nuclear Principles lead to actual policy changes, the anti-Japan critical front shared by North Korea and China [13][17][7] has the potential to translate into more concrete actions.

The fourth variable is the survival of working-level channels between North Korea and the United States. As seen in the case where Vice Department Director Kim Yo Jong dismissed talk of a summit as something she "knows nothing about" [18], the possibility of overt dialogue is low. However, the strategy of leaving room for maneuver through anonymous commentaries [2] suggests that the door for exploratory working-level contacts is not completely closed. Whether this channel is reactivated after the exercises will be a litmus test for the next phase.