The Indo-Pacific is rapidly emerging as the central theatre of global strategic competition. Unlike the Cold War in Europe, where nuclear deterrence involved two superpowers across relatively defined front lines, the Indo-Pacific presents a far more complex landscape. The region spans vast maritime distances, multiple potential flashpoints, and several nuclear-armed adversaries. North Korea continues to expand its nuclear and missile programs, China is rapidly increasing both the size and sophistication of its arsenal, and Russia maintains nuclear capabilities alongside a growing strategic presence in the Pacific.

In such an environment, the traditional model of extended deterrence, where the United States alone provides nuclear protection to its allies, may not be sufficient to address the scale and diversity of contingencies across the region. A new framework may be required, an Indo-Pacific nuclear alliance built on shared responsibility, distributed deterrence, and sovereign nuclear capabilities among key allies.

Complicating the adversary: The logic of distributed deterrence

At the core of such an alliance would ideally be sovereign nuclear deterrents for Australia, Japan, and South Korea. This model would resemble the role of the United Kingdom and France within NATO. Both maintain independent nuclear forces and sovereign decision-making, while contributing to the alliance’s broader deterrence posture.

Applying this model to the Indo-Pacific would significantly strengthen deterrence. If Australia, Japan, and South Korea each possessed sovereign nuclear capabilities, adversaries would face a far more complex strategic calculus. Rather than confronting a single decision-maker in Washington, they would need to account for multiple independent governments capable of responding to aggression.

This distributed architecture would complicate adversary planning and raise escalation risks. Any state considering coercion or military action against an Indo-Pacific democracy would have to account not only for the United States, but for several nuclear-capable regional powers with distinct strategic interests and decision-making processes.

Geography reinforces this logic. The Indo-Pacific spans an immense area, from the Korean Peninsula and Taiwan Strait to the South China Sea and the Indian Ocean approaches to Australia. The sheer distance between these theatres makes a purely centralized deterrence model increasingly difficult to sustain.

Flexible Deterrence through forward deployment and hosting

An Indo-Pacific nuclear alliance would therefore require forward deployment and hosting arrangements across the region. Australia, Japan, and South Korea could host a range of nuclear capabilities designed to provide flexible deterrent options across multiple contingencies.

These could include submarine-launched ballistic missiles (SLBM-N) on Ohio- and Columbia-class submarines; nuclear sea-launched cruise missiles (SLCM-N) on Virginia- and AUKUS-class submarines; B83 gravity bombs for platforms such as the B-2 Spirit and B-21 Raider, alongside the rearming of the B-52 Stratofortress and B-1B Lancer; B61 nuclear bombs for the B61 nuclear bombs for aircraft including the B-2, B-21, B-52, and F-35A Lightning II; and Long-Range Stand-Off (LRSO-N) nuclear cruise missiles for the B-21 and B-52. In addition, nuclear warheads could be assigned to land-based, mobile intercontinental ballistic missile (ICBM) launchers.

By dispersing these capabilities across multiple allied territories, the alliance would establish a more resilient and survivable deterrent posture. It would be far more difficult for an adversary to neutralize. Hosting arrangements would also strengthen operational integration among allied forces. As in NATO’s nuclear-sharing model, partner nations could contribute dual-capable platforms capable of delivering nuclear payloads in extreme circumstances.

Australia, Japan, and South Korea could commit to dual-capable submarine (DCS), aircraft (DCA), and land-based missile launcher (DCL) missions within the alliance structure. Dual-capable aircraft would provide visible and flexible deterrence signaling. Submarine-based systems would ensure a survivable second-strike capability across the region’s vast maritime domain. While land-based mobile missile launchers would add a credible and responsive ground-based deterrent, reinforcing the threat of rapid retaliation.

Such arrangements would distribute both responsibility and capability among Indo-Pacific allies, reducing the burden on the United States while strengthening the credibility of deterrence. It would transform the region from one dependent on a single guarantor into a networked system of mutually reinforcing nuclear deterrents.

Why the Philippines should revisit extended nuclear deterrence

An Indo-Pacific nuclear alliance would also require a reassessment of the policies of other regional partners. One notable example is the Philippines. For decades, the Philippines benefited from extended nuclear deterrence under its alliance with the United States. However, that relationship was complicated when the Philippines ratified the Treaty on the Prohibition of Nuclear Weapons (TPNW) in February 2021. By joining a treaty that prohibits the development, possession, and use—or threat of use—of nuclear weapons, the Philippines has distanced itself from reliance on the US nuclear umbrella.
This decision sits uneasily alongside the increasingly contested security environment in the South China Sea. If Manila wishes to strengthen its security relationship with the United States and regional partners, it may need to reconsider its position. Reintegrating into the framework of US extended nuclear deterrence would provide a stronger strategic backstop against coercion or aggression in its maritime domain.

Restoring strategic stability through credible, distributed deterrence architecture

Ultimately, the purpose of an Indo-Pacific nuclear alliance would not be to encourage proliferation for its own sake. Rather, it would be to restore strategic stability in a region where the balance of power is shifting rapidly.

Deterrence works best when it is credible, distributed, and resilient. In a region as vast and strategically complex as the Indo-Pacific, relying on a single nuclear guarantor may no longer provide the level of deterrence required to prevent conflict.

By adopting a model like the United Kingdom and France within NATO, where allied states maintain sovereign nuclear forces while contributing to a broader alliance deterrence posture, Australia, Japan, and South Korea could build a more stable and credible strategic architecture.

Such an arrangement would ensure that any adversary contemplating aggression in the Indo-Pacific would face not one nuclear power, but several, each capable of defending its sovereignty and contributing to the collective security of the region.

Natalie Treloar is the Australian Company Director of Alpha-India Consultancy, a Senior Fellow at the Indo-Pacific Studies Center (IPSC), a Senior Analyst at the National Institute for Deterrence Studies (NIDS), and a member of the Open Nuclear Network. Views expressed in this article are the author’s own.

Beyond a Pacific Defense Pact 4: Blueprint for an Indo-Pacific Nuclear Alliance was originally published on Global Security Review.

Although the technological details are simplified in the movie, its strategic intuition is right on point. A ballistic missile —possibly a Submarine Launched Ballistic Missile (SLBM) attributable to North Korea—creates a uniquely destabilizing crisis. The alert time is compressed, attribution gets ambiguous, and U.S. homeland missile defense becomes both the first and last line of defense. However, such a situation should not be a U.S. only issue especially in a West Pacific launch scenario, originating from the Sea of Japan or an adjacent maritime area. Both Japan and South Korean alliances present capabilities already in place or being actively pursued which could change the outcome.

Why SLBMs Create a Distinct Crisis?

SLBMs raise more profound challenges for interception than a land-based missile launched deep inside North Korean territory. The launch location is uncertain, early warning alerts could be delayed, while a credible trajectory may only be acquired after the boost phase. This compresses the U.S. leader’s decision-making cycle and complicates attribution at precisely the moment when clarity matters most.

Japan’s Role: Forward Maritime-Based Defense

Japan already fields many of the relevant capabilities to address . The Japanese Maritime SDF operates Aegis destroyers that are armed with SM-3 interceptors, including the SM-3 Block IIA variant that is co-developed with the United States. Under controlled experimental conditions, this interceptor has verified its ability to intercept ICBM-class targets, indicating that its strategic relevance goes beyond regional missile defense.

More importantly, Japan is moving towards a maritime-oriented ballistic missile defense posture. The planned Aegis System Equipped Vessels (ASEVs)—built around the SPY-7 radar—are designed to provide continuous BMD coverage without diverting multi-mission destroyers. Expected to be deployed in the late 2020s, these vessels would function as constant BMD platforms.

In an SLBM launch scenario in the Sea of Japan, such vessels could be ideally poised to detect, track, and intercept an SLBM that is transiting the Northern Hemisphere. Such forward deployment expands the interception theater, creating an opportunity for an early engagement before activating the missile defense situated in the continental United States. Therefore, Japan’s contribution is geometrical, not symbolic, shortening the initial time of engagement. 

South Korea’s Emerging Contribution

Similarly, South Korea is preparing to add the second crucial defense layer. Seoul is proceeding with the procurement of SM-3 missiles, reflecting the understanding that missile defense can no longer be restricted to terminal-phase defense on the Korean Peninsula. While South Korea’s existing air and missile defense system is centered on short- and medium-range threats, SM-3 introduces a new mission: sea-based midcourse interception.

South Korea’s Aegis destroyers equipped with SM-3s can operate in partnership with the Japanese defense forces in a complementary manner, creating azimuth diversity in intercept geometry. Multiple engagement opportunities from different angles to complicate an opponent’s countermeasures and lower the dependency on a single interception attempt. This is not mere redundancy, but resilience under uncertainty.

Another important element is South Korea’s push for a nuclear-powered submarine (SSN). Although an SSN does not intercept a missile, it influences the very unstable factor in this scenario: The North Korean submarine itself. While diesel-electric submarines rely on limited endurance and predictable operational patterns, SSNs can loiter, sprint, and conduct continuous operations across vast maritime areas. This makes it extremely difficult for North Korean submarines to reach actual launch areas undetected. In that sense, South Korea’s SSN ambition represents a denial strategy that could prevent the crisis from emerging, rather than serving as mere prestige or a symbol of a blue-water navy.

A Trilateral Layered Response

Pre-crisis posture is decisive. Japan’s ASEVs or Aegis destroyers should maintain BMD patrol points somewhere in the Sea of Japan, while South Korean Aegis destroyers could be operated near Korean waters in complementary sectors. Real-time information sharing through trilateral missile alert mechanisms should be a standing arrangement rather than an ad hoc measure.

At launch, forward sensors and shipborne radars could track earlier than what is portrayed in the movie—and if geometric conditions are met, Japanese naval vessels could attempt the first interception through SM-3 during early midcourse. Sequentially, South Korean destroyers could conduct a second round of engagement from different azimuths. To be sure, these attempts do not guarantee interception. Nevertheless, they reshape the problem from a terminal-phase gamble into a layered contest.

Only when these attempts fail would the engagement fall back to U.S. homeland defense; in this case, GBIs serve as the last line of defense rather than the sole response. At that juncture—when the U.S. must launch its GBIs—decision-makers would have more information, higher attribution credibility, and greater room for diplomacy to manage further escalation. The objective is not interception certainty, but the expansion of decision space under extreme uncertainty.

Policy Implications

If The House of Dynamite is a warning, the response should be concrete. Japan should recognize ASEVs as the backbone of regional BMD rather than as a peripheral capability. Meanwhile, South Korea should invest in the training, doctrine, and readiness required for sustained SM-3 operations. To be sure, together with the U.S., the three countries should institutionalize exercises that explicitly rehearse ICBM-class scenarios.

Although The House of Dynamite is a compelling drama, it is not destiny. The decisive factor is not technology itself, but alliance design, specifically whether Tokyo and Seoul are already in the fight when the crisis begins.

Dr. Ju Hyung Kim currently serves as a President at the Security Management Institute, in the South Korean National Assembly. He holds a doctoral degree in international relations from the National Graduate Institute for Policy Studies (GRIPS) in Japan, a master’s degree in conflict management from the Johns Hopkins University School of Advanced International Studies (SAIS), and a degree in public policy from Seoul National University’s Graduate School of Public Administration (GSPA). The views of the author are his own.

Fixing the House of Dynamite – An SLBM Crisis in East Asia was originally published on Global Security Review.