1. Introduction

The Trump administration's emphasis on greater allied burden-sharing and responsibility for regional security is raising fundamental questions across both the Pacific and Atlantic about how deterrence should be organized, how responsibilities should be divided, and how alliances can remain credible under conditions of growing strategic uncertainty. At the same time, the ongoing Iran War has exposed a related but increasingly urgent problem: whether the United States and its allies have the stockpiles, industrial capacity, logistics, and infrastructure resilience needed to sustain prolonged high-intensity operations.

These pressures are unfolding simultaneously in Asia and Europe, encouraging the two regions to speak in an increasingly common strategic vocabulary. Terms such as deterrence, strategic stability, resilience, and alliance management have gained new urgency as allies reassess how they prepare for increasingly demanding security environments. Both regions are also turning to similar capabilities and strategic approaches. Deep-precision strike (DPS), intelligence, surveillance, and reconnaissance (ISR), cyber capabilities, and AI-enabled systems are gaining prominence in both theaters, while extended nuclear deterrence continues to provide the ultimate security backstop. Yet similarities in these responses do not mean that their underlying strategic logic travels easily across theaters.

Against this backdrop, this article examines the similarities and differences between the Asian and European theaters. The purpose is not to assume that concepts or practices developed in one region can simply be transferred to the other, but to identify where meaningful lessons can be drawn, where important differences must be recognized, and where greater cross-regional cooperation may be possible in an increasingly volatile security environment. The paper proceeds in three parts. The first section examines the substantive differences between the Asian and European theaters. The second turns to challenges that persist across both regions despite these differences. The third identifies areas where more concrete cross-regional cooperation may be feasible and what each region can learn from the other.

2. Two Distant Theaters, Different Realities

Threat Perception and Geography

Asia and Europe confront adversaries of a fundamentally different character. Russia is conventionally weaker than NATO but remains a nuclear peer capable of posing an existential threat to exposed European allies, while China represents a more formidable long-term competitor, particularly in the maritime domain. Consequently, the European theater is predominantly continental and land-oriented, while East Asian contingencies are more maritime and air-centric, creating different demands for capabilities, reinforcement, and targeting. Geography also shapes how directly each threat is felt. South Korea faces an immediate North Korean threat, while European allies, especially those exposed along the Baltic and High North, face a more geographically proximate Russian threat, producing different strategic priorities and operational requirements within Europe. Given the differing familiarity with each theater's operating environment, allies are likely to prioritize their own regions rather than assume seamless cross-theater reinforcement.

Nuclear and Alliance Architecture

The material and institutional foundations underpinning deterrence also differ between the two theaters. Europe has two nuclear-armed allies, the United Kingdom and France, alongside U.S. extended deterrence in the framework of NATO, giving it a broader distribution of nuclear capabilities than East Asia. South Korea and Japan remain non-nuclear and depend more directly on U.S. nuclear guarantees despite their increasingly advanced conventional capabilities.

Then, these differences are reinforced by differences in alliance structures. In Europe, NATO is highly institutionalized but multilateral, requiring consensus among its 32 members and maintaining a degree of separation between nuclear and conventional planning. By contrast, U.S. alliances in Asia are predominantly bilateral and organized through a hub-and-spoke model, with the ROK-U.S. alliance standing out for its tight operational integration through the Combined Forces Command. The establishment of the Nuclear Consultative Group (NCG), together with efforts to link allied conventional capabilities with U.S. nuclear forces through conventional-nuclear integration (CNI), further distinguishes the ROK-U.S. alliance. Shortly put, Europe possesses a broader distribution of deterrence capabilities but faces greater challenges of multilateral coordination, while alliances in East Asia rely more on U.S. extended deterrence but seek to benefit from a more integrated bilateral mechanisms for consultation, planning, and decision-making, including the nuclear realms.

Approach to Deterrence and Strategic Stability

Another interesting point of divergence lies in how the term "strategic stability" is conversed differently in Asia and Europe. In South Korea, strategic debates have tended to focus primarily on strengthening deterrence credibility in response to an immediate and growing North Korean nuclear threat. Questions of capability, assurance, and the credibility of U.S. extended deterrence therefore occupy a central place in their strategic discourses. In Europe, on the other hand, deterrence has more often been embedded within a broader conception of strategic stability that also encompasses risk reduction, arms control, crisis communication, and the management of mutual vulnerability.

This difference does not mean that one theater prioritizes deterrence while the other prioritizes restraint. Rather, it reflects different historical experiences and strategic traditions. Norway's Cold War approach, for example, sought to combine credible defense with reassurance and self-imposed restraints designed to reduce unnecessary Soviet threat perceptions. South Korea has accumulated less experience with this type of institutionalized risk reduction, although the ROK-U.S. NCG has begun to incorporate related elements. Greater cross-regional exchange could therefore help broaden discussions of deterrence in Asia beyond the question of how to strengthen capabilities toward the equally important question of how stronger capabilities can be managed without generating additional instability.

3. Shared Challenges Across Two Theaters

The Conventional Paradox

Despite their different strategic environments, Asia and Europe confront a similar paradox as they strengthen conventional capabilities to assume greater responsibility for regional defense. Deep precision strike, ISR, missile defense, cyber capabilities, and AI-enabled targeting can strengthen deterrence by improving denial and punishment options below the nuclear threshold. For non-nuclear U.S. allies in Asia in particular, advanced conventional capabilities inevitably play a central role in compensating for nuclear asymmetry.

Yet greater conventional strength is not automatically stabilizing. Capabilities designed for conventional deterrence may also threaten an adversary's nuclear forces, leadership, or command-and-control, creating incentives for further arms buildup or even preemption. In Europe, this problem is particularly acute where conventional targets overlap with or sit close to Russian strategic assets, while on the Korean Peninsula advanced strike and ISR capabilities may generate similar concerns about the survivability of North Korea's nuclear forces and leadership. Large-scale conventional strike options may therefore appear strategically threatening even when they remain below the nuclear threshold.

The common challenge in both theaters is that capability development has moved faster than strategic thinking about how these forces would actually contribute to deterrence without generating additional instability. The effects of advanced conventional capabilities ultimately depend not only on their size or sophistication, but also on doctrine, targeting, political control, adversary perceptions, and the speed of decision-making.

Escalation Management, War Aims, and War Termination

A related but distinct challenge arises once deterrence begins to fail and military force is actually employed. In both Asia and Europe, the central question then becomes not simply what capabilities are available, but what political objectives military operations are intended to achieve, how much force is proportionate to those objectives, and where escalation should stop.

This dilemma is particularly visible on the Korean Peninsula, where conventional objectives such as advancing into North Korean territory could create existential pressure on Pyongyang and potentially increase incentives for nuclear use. In Europe, conventional operations against targets connected to Russia's strategic forces or command-and-control could create comparable escalation pressures. The difficulty in both theaters is therefore to distinguish military actions necessary to achieve limited objectives from those that an adversary may perceive as threatening regime survival or strategic deterrent forces.

Escalation management must consequently begin with political objectives and war aims rather than tactical response options alone. Allies in both Asia and Europe therefore need to consider in advance what constitutes an acceptable end state, what costs they are willing to bear, and how military operations can remain aligned with political objectives and war-termination goals as escalation unfolds.

The DPRK-Russia Nexus as a Cross-Theater Challenge

One increasingly important point of convergence between the two theaters is the deepening military relationship between North Korea and Russia. For South Korea and other Asian allies, Russian support can contribute to improvements in North Korea's nuclear and conventional capabilities, provide operational experience from the ongoing warfare, and complicate calculations about possible third-party intervention in a future crisis on the Korean Peninsula. For Europe, North Korean troops, ammunition, missiles, and other forms of support have contributed directly to Russia's ability to sustain its war in Ukraine.

The significance of this relationship therefore extends beyond bilateral DPRK-Russia cooperation. It demonstrates how developments in one theater can alter the military balance and strategic calculations in the other. Developing a more common assessment of the Russia-North Korea nexus could consequently provide a practical starting point for Asia-Europe strategic cooperation and for considering how simultaneous or overlapping contingencies could create opportunities for adversaries across theaters.

Communication, Signaling, and Risk Reduction

Asia and Europe also face a common problem of communicating the limits and purposes of military action under increasingly compressed crisis conditions. Effective deterrence in both theaters requires more than demonstrating resolve. It also requires reassurance: adversaries must understand not only that aggression will incur costs, but also that restraint will not be exploited and that refraining from further escalation can lead to a safer outcome. In both theaters, direct communication channels are limited, conventional and nuclear forces are becoming more entangled, and AI-enabled systems and faster operational processes are compressing the time available for political judgment. The effectiveness of a signal therefore depends not only on what the sender intends, but on how the adversary interprets it.

4. Policy Recommendations: Linking the Two Theaters

Regional Specialization and Cross-Theater Coordination

Cooperation between Europe and Asia should begin with a realistic understanding of geographical distance and difference. Neither region can easily project and sustain major military power in the other's theater, particularly if conflicts happened at the same time, and their different theater priorities make a shared war plan unrealistic. Yet, as this article illustrated, the two theaters are increasingly connected. Russia's deepening military cooperation with North Korea already shows how developments in one region can affect the other, while a major war in East Asia that absorbs U.S. attention and capabilities could create opportunities for Russia in Europe. The practical answer is therefore not to erase the distinction between the two theaters, but to combine regional specialization with cross-theater coordination. South Korea should remain focused primarily on the Korean Peninsula and its surrounding region, while European allies concentrate on deterring Russia, with cooperation focused on areas where both sides can strengthen resilience and reduce common vulnerabilities.

Strengthen Reassurance and Strategic Signaling

Both Asian and European allies can discuss how their declaratory policy can be reinforced by private communication, military posture, targeting choices, and other non-verbal signals. Exercises and war games should also incorporate adversary perspectives to test how actions intended as proportionate, restrained, or reassuring might instead be interpreted as preparation for escalation. The shared challenge is ultimately the same: how to combine credible deterrent capability with sufficient restraint and communication to prevent military advantage from generating greater strategic instability.

Institutionalize a Recurring Track 1.5 Dialogue

A recurring Track 1.5 dialogue could provide the institutional mechanism for sustaining this agenda. Rather than creating another broad regional forum, it should remain problem-driven and bring together government practitioners and experts to examine specific issues that both theaters confront but rarely address together. Priority subjects could include conventional-nuclear integration, targeting, war aims, crisis communication, escalation control, and the interpretation of adversary behavior.

Scenario-based discussions and war games could serve as practical tools within this dialogue. Participants could compare how North Korea, Russia, or China might interpret allied actions, test how apparently proportionate or reassuring measures could be misread, and identify which practices developed in one theater may or may not be applicable in the other. The purpose would not be to develop a common operational approach, but to build a sustained process of cross-regional learning while preserving the important strategic differences between Asia and Europe.

Pinpoint Cooperation on AI, Cyber, and Space

Cross-theater cooperation should also concentrate on a limited number of functional areas where Asia and Europe face increasingly similar technological and industrial challenges. Particularly promising areas include cyber, space, AI and autonomous systems, and selected intelligence sharing. These capabilities are becoming increasingly important to deterrence in both theaters, while their underlying industrial and technological ecosystems are themselves increasingly interconnected. AI and autonomous systems deserve particular attention because they may improve ISR, targeting, and decision support while simultaneously compressing decision time and increasing the risk that operational speed outpaces political judgment. Cooperation should therefore address not only how these technologies can strengthen military effectiveness, but also how they can be employed without creating unnecessary escalation risks.

Continue NATO-IP4 Cooperation

NATO-IP4 cooperation can provide a useful framework for linking Asian and European partners, but its purpose should remain practical rather than institutional. The IP4 should not be treated as a new alliance or as a substitute for existing U.S.-led bilateral alliances. Instead, it can help connect bilateral and minilateral relationships and facilitate cooperation in areas where Asian and European partners share concrete interests. For South Korea, this may mean maintaining strong bilateral relationships while using the IP4 framework selectively to connect them. Japan has particular operational relevance to contingencies on the Korean Peninsula because of its geography and role in hosting U.S. forces, while Australia and New Zealand contribute in different ways.

Strengthen Asia-Europe Linkages without Weakening U.S. Engagement

Ultimately, the broader purpose of linking the two theaters is not to hedge against the U.S., but to reduce the risks that come from uncertainty about its future priorities and capacity. For European allies, this means taking greater responsibility for regional defense and developing European and Nordic capabilities that can help fill gaps if Washington shifts more attention toward the Indo-Pacific. South Korea faces a different constraint. Its dependence on U.S. extended deterrence and the immediacy of the North Korean nuclear threat leave much less room for traditional strategic hedging, making capability diversification and resilience more realistic goals. The common challenge is therefore how to strengthen allied capabilities without encouraging greater U.S. disengagement. Greater Asian and European capacity should demonstrate burden-sharing, clarify regional responsibilities, and reduce vulnerabilities in areas such as defense production and supply chains, while still reinforcing the credibility of U.S. commitments. In this sense, growing linkages in the Asia and European allies should complement the alliance rather than replace it, allowing allies to become more capable of managing regional crises without assuming that they can or should operate independently of the United States.

1. This article is outcome of discussions among ROK and Norwegian experts at the Sejong Institute-Norwegian Institute for Defence Studies (IFS) Kick-off Seminar, held in Seoul on September 11, 2026. The seminar was sponsored by IFS and co-hosted by the Sejong Institute and IFS as part of a joint project aimed at strengthening strategic linkages and policy dialogue among South Korea, Norway, Europe/NATO, Japan, and the United States.

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