NATO’s recent establishment of Baltic Sentry (2025), Eastern Sentry (2025), and Arctic Sentry (2026) reflects more than a response to Russian aggression. Collectively, these operations demonstrate how modern deterrence has evolved to address persistent airspace violations, hybrid warfare, cyber-attacks, sabotage of critical infrastructure, and grey-zone coercion. While these missions are conventional military operations, they derive their strategic credibility from something far more significant, NATO’s integrated nuclear deterrence architecture.

This distinction is critical. NATO’s Sentry operations are not isolated military activities; they are conducted within an alliance whose conventional forces are underwritten by the collective nuclear capabilities of the United States, the United Kingdom, and France. Any adversary contemplating escalation understands that conventional confrontation with NATO carries the inherent risk of nuclear escalation. This integration between conventional and nuclear deterrence has underpinned Euro-Atlantic security for more than seventy years.

For the Indo-Pacific, the lesson is clear. As China rapidly expands its nuclear arsenal, North Korea continues to develop increasingly sophisticated nuclear and missile capabilities, and Russia under Vladimir Putin has revived Cold War-era nuclear coercion, regional allies cannot assume that conventional military cooperation alone will provide credible deterrence. If deterrence is to succeed, it must be built upon a coherent nuclear alliance before a crisis emerges, not after deterrence has already failed.

Conventional Operations Backed by Nuclear Deterrence

The strategic significance of NATO’s Sentry operations lies not simply in what they do, but in what stands behind them. Baltic Sentry enhances surveillance and protection of undersea communications cables, energy infrastructure, and maritime approaches following repeated acts of sabotage and suspicious activity in the Baltic Sea. Eastern Sentry reinforces NATO’s eastern flank through enhanced air policing, intelligence sharing, and rapid response capabilities in the face of persistent Russian military activity. Arctic Sentry reflects NATO’s growing focus on the High North as Russia and China expand their military presence in an increasingly contested region.

These operations improve situational awareness, interoperability, and alliance readiness. Yet none of them exist in isolation. Their credibility stems from NATO’s integrated command structure, collective defense commitments under Article 5 of the North Atlantic Treaty, shared military planning, and, fundamentally, the Alliance’s nuclear deterrence posture. NATO’s Nuclear Planning Group, alongside the independent nuclear forces of the United Kingdom and France and the United States extended nuclear deterrence commitments, ensures that any conventional confrontation carries strategic consequences far beyond the immediate theater.

This layered approach to deterrence is central to NATO’s success. Conventional operations deter day-to-day coercion, while nuclear deterrence prevents adversaries from believing they can escalate a conventional conflict without unacceptable consequences. The two cannot be separated; together they create a coherent deterrence architecture.

The Indo-Pacific’s Strategic Environment Has Changed

The Indo-Pacific now faces a security environment increasingly defined by nuclear competition. China’s rapid expansion and modernization of its nuclear arsenal is reshaping the regional balance of power. At the same time, Beijing continues to employ sustained grey-zone coercion through military pressure around Taiwan, coercive operations in the South China Sea, cyber campaigns, and increasingly frequent air and maritime incursions directed at neighboring states.

North Korea’s advancing nuclear weapons and ballistic missile programs add another layer of strategic complexity. Pyongyang’s continued weapons development increases the likelihood that any regional crisis could involve nuclear coercion or escalation.

Meanwhile, Russia’s full-scale invasion of Ukraine has demonstrated that nuclear weapons remain central to great-power competition. Throughout the conflict, President Vladimir Putin has repeatedly employed nuclear rhetoric and strategic signaling to deter Western intervention. The assumption that the end of the Cold War marked the end of nuclear coercion has proven false.

For Indo-Pacific allies, this means they are confronting not one, but three nuclear-armed challengers whose strategic interests increasingly overlap. Yet the region’s security architecture remains fragmented.

The Missing Foundation

The United States maintains strong bilateral alliances with Australia, Japan, South Korea, and the Philippines. Regional initiatives such as AUKUS and the Quad have strengthened defense cooperation, technological collaboration, and strategic coordination. These arrangements make important contributions to regional security.

However, they do not constitute an integrated alliance comparable to NATO. They lack common command arrangements, formalized collective defense obligations across the region, institutionalized nuclear consultation mechanisms, and a unified framework for integrating conventional and nuclear deterrence. This matters because conventional military cooperation alone cannot provide fully credible deterrence against nuclear-armed adversaries. NATO’s experience demonstrates that conventional operations derive their strategic weight from the knowledge that they are backed by a credible and integrated nuclear alliance. Without that strategic foundation, conventional activities risk being viewed as isolated demonstrations of resolve rather than components of a comprehensive deterrence posture. The Indo-Pacific is therefore attempting to strengthen conventional deterrence without first establishing the alliance architecture that gives such deterrence its greatest credibility.

Building Deterrence Before Crisis

History consistently demonstrates that alliances formed during conflict rarely prevent that conflict. They manage its consequences instead. Europe’s recent experience illustrates this lesson. Many of NATO’s most significant reforms, including enhanced forward deployments,

strengthened infrastructure protection, expanded readiness, and the establishment of the Sentry operations, were accelerated in response to deteriorating security conditions following Russia’s aggression against Ukraine. They represent adaptation after strategic warning signs became impossible to ignore.

The Indo-Pacific still has an opportunity to act before reaching a comparable point. Rather than waiting for a crisis over Taiwan, the South China Sea, or the Korean Peninsula to force hurried institutional change, regional democracies should begin developing the alliance structures necessary to sustain credible deterrence.

Such an alliance would not require every member to possess nuclear weapons. Instead, it would integrate conventional planning with extended nuclear deterrence, establish mechanisms for strategic consultation, coordinate contingency planning, strengthen interoperability, and ensure that regional conventional operations are supported by a credible nuclear deterrent capable of deterring nuclear-armed adversaries.

Conclusion

NATO’s Baltic Sentry, Eastern Sentry, and Arctic Sentry operations are not simply conventional military initiatives. They are visible expressions of a much deeper strategic reality: conventional deterrence is most credible when backed by an integrated nuclear alliance. Their effectiveness rests not only on ships, aircraft, and surveillance systems, but on the certainty that any attempt to escalate against NATO would confront the Alliance’s collective nuclear deterrent.

The Indo-Pacific faces an increasingly dangerous strategic environment characterized by a rapidly expanding Chinese nuclear arsenal, an emboldened North Korea, and a resurgent Russia that has returned nuclear coercion to the center of international politics. In such an environment, conventional cooperation alone is unlikely to provide sufficient deterrence.

The central lesson from NATO’s Sentry operations is therefore not that the Indo-Pacific should simply replicate these missions. It is that such operations derive their credibility from the nuclear alliance that stands behind them. Waiting to build that alliance until deterrence has failed would repeat the strategic mistakes history has repeatedly exposed. The time to establish an integrated Indo-Pacific nuclear alliance is before a crisis begins, not after conflict has already become unavoidable.

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

NATO’s Sentry Operations Show Why the Indo-Pacific Needs a Nuclear Alliance was originally published on Global Security Review.

The Indo-Pacific is entering a period of acute strategic imbalance. China’s rapid military modernization across nuclear, conventional, cyber, and space domains has outpaced the ability of regional powers to respond through traditional force buildup alone. While governments often default to expanding conventional capabilities with more ships, missiles, aircraft, and bases, this approach is slow, expensive, and increasingly insufficient against a peer competitor with both scale and nuclear backing. By contrast, forming an Indo-Pacific nuclear alliance offers a faster, more credible way to close the deterrence gap. 

Crucially, this challenge is not just about China. The region faces a multi-nuclear threat environment that includes an increasingly capable North Korea and a resurgent Russia, willing to use nuclear and conventional signaling to shield conventional aggression. The cumulative effect of these actors compresses decision-making time and raises the stakes of deterrence failure. At its core, the argument is about time, credibility, and strategic effect. 

The Time Problem: Conventional Forces Are Slow to Build 

Modern conventional military capability is not something that can be generated quickly. Building advanced submarines, fifth-generation aircraft, integrated air and missile defense systems, or long-range strike capabilities takes years—often decades. For example. Australia’s plan to acquire nuclear-powered submarines under Pillar I will not deliver operational capability until the late 2030s or early 2040s. As a stopgap. rotational deployments and being considered in the interim. However, these do not fully close the capability gap. 

Similarly, scaling up missile production, hardening bases, and integrating joint command systems across the region require sustained industrial mobilization. Western defense industries, particularly in the United States, are already under strain from commitments in Europe and the Middle East. Expanding production lines for precision munitions or advanced systems is constrained by supply chains, workforce shortages, and political processes. 

In short, conventional rearmament is a long game. The strategic environment in the Indo-Pacific, however, is deteriorating on a much shorter time scale. 

A Multi-Nuclear Threat Environment 

Focusing solely on China understates the scale of the challenge. The Indo-Pacific is increasingly shaped by three distinct nuclear pressures: 

• China is expanding and diversifying its nuclear arsenal at a pace not seen in decades, while integrating it more closely with conventional operations. 
• North Korea continues to refine its nuclear weapons and delivery systems, including intercontinental ballistic missiles capable of reaching the United States and regional allies. Kim Jong Un has also signaled a lower threshold for potential nuclear use in a crisis. 
• Russia, while geographically more distant, remains an Indo-Pacific actor through its Far East presence and strategic alignment with China. Its behavior during the war in Ukraine under the shadow of nuclear threats demonstrates how nuclear coercion can enable prolonged conventional conflict. 

This layered nuclear environment complicates deterrence. It is no longer about balancing a single adversary, but managing overlapping deterrence relationships, where escalation in one theater can have cascading effects in another. 

The Deterrence Gap: Nuclear-Backed Coercion 

China’s growing nuclear arsenal fundamentally alters the deterrence equation. While conventional forces can impose costs, they cannot fully offset the coercive power of nuclear weapons. Beijing can leverage its nuclear capabilities to deter external intervention in a regional conflict, particularly over Taiwan, while using conventional forces to achieve fait accompli. North Korea adds a different kind of instability. It has a smaller but less predictable nuclear force, with a demonstrated willingness to engage in brinkmanship. Meanwhile, Russia’s nuclear posture reinforces a broader norm, that nuclear weapons can be used to shield aggression and shape adversary behavior via threats of use. 

This creates a deterrence asymmetry: regional states may possess capable conventional forces, but without nuclear backing, their ability to deter escalation is limited. The United States provides extended nuclear deterrence, but questions about credibility, response timelines, and escalation risks persist, especially as adversaries develop capabilities to target bases in the United States and nuclear command, control, and communications (NC3) systems. 

The Speed Advantage of a Nuclear Alliance 

A nuclear alliance can be established far more rapidly than building conventional parity. Unlike ships or aircraft, nuclear deterrence is not primarily about quantity. Instead, it is about credibility, survivability, and signaling. 

Consider NATO. Its nuclear sharing arrangements allows non-nuclear members to participate in nuclear planning, host nuclear weapons, and integrate delivery systems without developing their own arsenals. This framework was established quickly during the Cold War and endured for decades as a cornerstone of deterrence. 

An Indo-Pacific equivalent could replicate key elements of such an arrangement: 

• Forward deployment or rotational presence of U.S. nuclear-capable assets 
• Nuclear-sharing arrangements with trusted allies such as Japan, South Korea, and potentially Australia 
• Integrated nuclear-planning mechanisms to ensure regional input into deterrence strategy 
• Hardened and distributed basing to enhance survivability 

These steps do not require decades of industrial buildup. They rely on political decisions, alliance coordination, and doctrinal integration. These are areas where progress can be made over years, not decades. 

Credibility Through Integration 

Deterrence is about perception. Adversaries must believe that the costs of aggression will outweigh the benefits. A nuclear alliance enhances credibility in several ways. 

First, it raises the stakes of conflict. If multiple states are integrated into a nuclear deterrence framework, any aggression risks broader escalation. This complicates an adversary’s planning and reduces the likelihood of limited, opportunistic actions. 

Second, it distributes risk and responsibility. Extended deterrence is more credible when allies are actively involved in nuclear planning and posture. This reduces doubts about whether the United States would act alone in a crisis. 

Third, it signals resolve and unity. Formalizing nuclear cooperation sends a clear message, that the region is prepared to escalate, if necessary, rather than relying solely on conventional responses that may be insufficient. 

Cost and Efficiency 

Conventional rearmament is not only slow, but it is extraordinarily expensive. Building fleets of advanced platforms, sustaining them, and integrating them into joint operations imposes massive fiscal burdens. 

A nuclear alliance, by contrast, leverages existing capabilities. The United States already possesses a robust nuclear arsenal and delivery systems. The marginal cost of extending deterrence through alliance structures is significantly lower than building new conventional forces from scratch. 

For middle powers like Australia, Japan, and South Korea, this is particularly important. Attempting to match China’s conventional military growth is economically unsustainable, let alone simultaneously accounting for North Korean and Russian contingencies. A nuclear alliance provides a cost-effective way to achieve strategic balance across these multiple threats. 

Addressing Political and Normative Challenges 

Of course, forming a nuclear alliance in the Indo-Pacific is not without challenges. Non-proliferation norms, domestic political sensitivities, and regional perceptions all complicate the issue. Countries like Japan have strong anti-nuclear culture which is shaped by history. Australia has long positioned itself as a supporter of non-proliferation. Any move toward nuclear sharing or hosting would require careful political management and public communication. 

However, these constraints are not insurmountable. NATO demonstrates that nuclear sharing can coexist with non-proliferation commitments under the Nuclear Non-Proliferation Treaty framework. The key is transparency, adherence to legal obligations, and a clear defensive rationale. Moreover, the strategic environment is changing. As the combined pressures from China, North Korea, and Russia intensify, the political calculus around deterrence may shift accordingly. 

Complement, Not Replacement 

A nuclear alliance is not a substitute for conventional forces. Rather, it is a force multiplier. Conventional capabilities remain essential for day-to-day operations, crisis management, and limited conflicts. 

However, without credible nuclear backing, conventional forces risk being outmatched in scenarios where nuclear-armed adversaries control escalation. The most effective approach is a layered deterrence strategy: 

• Nuclear deterrence to prevent large-scale war and coercion 
• Conventional forces to deny and punish aggression 
• Resilience measures to ensure continuity under attack 

A nuclear alliance strengthens the top layer of this structure, enabling the others to function more effectively across multiple threat vectors. 

Conclusion: Speed Matters in a Multi-Threat Era 

The Indo-Pacific does not have the luxury of time or the simplicity of a single adversary. Conventional rearmament, while necessary, cannot close the deterrence gap quickly enough to match the pace of strategic change driven by China, North Korea, and Russia. 

An Indo-Pacific nuclear alliance offers a faster path to credible deterrence. By leveraging existing capabilities, enhancing integration, and signaling resolve, it can stabilize the regional balance in the near term, while stalling for longer-term conventional investments to mature.  

The choice is not between nuclear and conventional approaches, but between acting quickly or falling behind. In a rapidly shifting, multi-nuclear strategic environment, speed is not just an advantage. It is a necessity. 

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 are the author’s own.

An Indo-Pacific Nuclear Alliance Closes the Deterrence Gap Faster than Conventional was originally published on Global Security Review.

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.

Strategic competition in the Indo-Pacific increasingly occurs in the grey zone, the space between routine statecraft and open armed conflict. China, North Korea, Russia, and Iran employ a range of coercive tactics designed to alter the strategic environment without triggering a conventional military response. These activities include cyber operations, maritime harassment, disinformation campaigns, economic coercion, and limited military provocations. Because these actions remain deliberately below the threshold of war, they often exploit the reluctance of states to respond with force. As grey zone competition intensifies, the question confronting policymakers is not only how to deter such activities, but also how to ensure that responses to them are credible. In this context, a nuclear alliance could serve as the ultimate strategic backstop for military responses to persistent grey zone coercion.

Grey zone strategies rely heavily on ambiguity and escalation management. The states that employ these tactics understand that their adversaries—particularly democratic states—are cautious about escalating disputes into major military confrontations. By operating just below the threshold of armed conflict, grey zone actors seek to gradually erode the strategic position of their opponents while avoiding a decisive response. Maritime coercion in disputed waters, persistent airspace incursions, cyber intrusions, and limited military demonstrations all serve this purpose. Over time, these actions can reshape the operational environment, undermine alliances, and weaken the credibility of deterrence.

The difficulty lies in crafting responses that are both proportionate and credible. Conventional military responses to grey zone activities risk escalating a crisis if they are perceived as excessive, yet insufficient responses can embolden further coercion. This dilemma has led analysts to argue that deterrence in the grey zone requires a layered approach that combines political, economic, and military tools. However, even robust conventional responses may prove insufficient if adversaries believe that escalation dominance ultimately rests in their favor. It is in this context that nuclear deterrence retains enduring strategic relevance.

A nuclear alliance would not be designed to deter grey zone activities directly. Nuclear weapons are instruments of last resort intended to deter existential threats and large-scale conventional aggression. Nevertheless, the presence of a credible nuclear backstop fundamentally shapes the broader strategic environment in which grey zone competition occurs. By reinforcing the credibility of allied military responses, nuclear deterrence can prevent grey zone crises from escalating into major wars while simultaneously discouraging adversaries from testing the limits of conventional deterrence.

In practical terms, a nuclear alliance would strengthen escalation management in the Indo-Pacific. If regional states believed that their security rested on a collective nuclear deterrent, they would be better positioned to respond firmly to grey zone provocations. Maritime patrols, cyber countermeasures, and limited military deployments could be undertaken with greater confidence that adversaries would hesitate to escalate beyond the conventional level. In this sense, nuclear deterrence functions as a strategic umbrella under which lower-level military responses can occur without triggering uncontrolled escalation.

The experience of the Cold War offers a useful historical precedent. During that period, the North Atlantic Treaty Organization relied on nuclear deterrence to prevent large-scale aggression by the Soviet Union while simultaneously engaging in conventional competition across multiple domains. Although grey zone tactics—including espionage, proxy conflicts, and political interference—were common, the presence of a credible nuclear deterrent helped ensure that such competition did not escalate into direct war between nuclear powers. A similar logic could apply in the Indo-Pacific today.

In the contemporary regional context, a nuclear alliance could involve close coordination among the United States and key Indo-Pacific partners. Such an arrangement would not necessarily require the proliferation of nuclear weapons. Instead, it could mirror existing extended deterrence frameworks in which nuclear-armed states provide security guarantees to non-nuclear allies while maintaining operational control over nuclear forces. Through mechanisms such as joint planning, strategic consultation, and integrated command structures, allied states could strengthen the credibility of collective deterrence without undermining existing non-proliferation commitments.

Importantly, a nuclear backstop would also reinforce political resolve among allied states. Grey zone strategies often aim to exploit divisions within alliances by testing whether partners will respond collectively to incremental coercion. If adversaries perceive hesitation or disunity, they may conclude that the risks of escalation are manageable. A formal nuclear alliance could signal a high level of strategic commitment among participating states, thereby increasing the perceived costs of continued grey zone pressure.

Critics may argue that linking nuclear deterrence to grey zone competition risks lowering the nuclear threshold or introducing unnecessary escalation dynamics. These concerns highlight the importance of clearly defining the role of nuclear weapons within a broader deterrence framework. The objective would not be to threaten nuclear retaliation for minor provocations, but rather to ensure that adversaries understand that attempts to escalate beyond the grey zone could encounter a unified and credible deterrent response. In this sense, nuclear deterrence functions as a stabilizing force that sets clear limits on how far coercion can be pushed.

As the Indo-Pacific becomes the central arena of strategic competition, the persistence of grey zone tactics will continue to test existing security arrangements. States that rely solely on conventional responses may find themselves locked in a cycle of incremental coercion that gradually shifts the balance of power. By contrast, a nuclear alliance would provide a strategic foundation that reinforces the credibility of allied military responses across the escalation spectrum.

Ultimately, understanding grey zone actors and the tactics they employ is essential for effective deterrence. Yet deterrence also requires credible escalation management and the assurance that adversaries cannot exploit the space between peace and war indefinitely. In the Indo-Pacific, a carefully structured nuclear alliance could provide the strategic backstop necessary to ensure that responses to grey zone coercion remain both credible and effective while preventing escalation into catastrophic conflict.

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 3: A Nuclear Alliance as the Ultimate Backstop to Grey Zone Coercion was originally published on Global Security Review.

The Indo-Pacific is entering a far more dangerous strategic era. Military modernization, grey-zone coercion, and rapid nuclear expansion are reshaping the regional balance of power. Most notably, China is undertaking a historic expansion of its nuclear arsenal, investing in silo fields, road-mobile intercontinental ballistic missiles, ballistic missile submarines, and dual-capable systems. Simultaneously, Russia’s willingness to use nuclear threats in Europe demonstrates that nuclear coercion is once again central to great-power competition.

In Washington, proposals such as Ely Ratner’s Pacific Defense Pact reflect recognition that the current security architecture is insufficient. A more formalized collective defense structure in the Indo-Pacific is necessary.

However, this is not sufficient. A conventional Pacific Defense Pact does not fully address the most dangerous level of escalation to large-scale conventional war or nuclear attack. What the region now requires is a narrowly defined Indo-Pacific nuclear alliance.

A Narrow, Explicit Purpose

This would not be a sweeping defense pact covering every maritime incident, border clash, cyber intrusion, or grey-zone coercive act. It would have a clear and carefully delimited purpose. That is to deter large-scale conventional war or nuclear attack against member states.

Its clarity would be its strength. That clarity performs a second vital function. It minimizes the risk of entrapment by ensuring member states are not dragged into escalation over actions below the threshold of war. By explicitly excluding grey-zone coercion and limited crises from its nuclear remit, the alliance would reassure leaders that only truly existential threats trigger its highest-level commitments.

Participation becomes politically sustainable and strategically credible because it avoids automatic escalation over incremental provocations. The alliance would draw a line at catastrophic strategic aggression.

The Historical Record: Why Nuclear Deterrence Matters

The case for a nuclear alliance is not theoretical. It is grounded in historical experience. During the Cold War, nuclear parity between the United States and the Soviet Union prevented direct large-scale war and nuclear attack in Europe. Despite ideological confrontation and proxy conflicts, neither side attempted a conventional war or nuclear attack on the other’s core territories. Nuclear weapons imposed restraint. They deterred not just nuclear use, but overwhelming conventional assault.

Similarly, within NATO, the presence of U.S. nuclear guarantees has prevented full-scale Russian conventional attack on Alliance territory. Moscow has tested boundaries through

hybrid tactics and coercive signaling, but it has not launched a large-scale attack on NATO soil. Nuclear deterrence at the alliance level raised the costs to an unacceptable threshold.

The 1969 Sino-Soviet border conflict further illustrates how nuclear capability constrains escalation. The Soviet Union’s nuclear superiority allowed it to signal credible threats, while China’s emerging nuclear capability and mobilization signaled resolve. Mutual fear of escalation compelled negotiation, including intervention through U.S. triangular diplomacy. Nuclear weapons shaped behaviors without being used.

The India–Pakistan experience is equally instructive. Prior to overt nuclearization, the two states fought multiple full-scale wars. Since their nuclear tests in 1998, crises have erupted, but they have remained limited. Missile strikes, cross-border skirmishes, and periods of great tension have not escalated into all-out conventional war or nuclear attack. Nuclear deterrence imposed a ceiling on the conflicts.

Contrast this with the Russia–Ukraine war. Ukraine relinquished its nuclear arsenal in the 1990s and now confronts a nuclear-armed Russia without possessing its own nuclear deterrent. The result has been a prolonged and costly conventional war of attrition. The absence of mutual nuclear deterrence has made sustained large-scale conventional war possible. By comparison, Russia has not launched a direct assault on NATO territory precisely because nuclear deterrence underwrites NATO’s collective defense.

The pattern is clear. Where credible nuclear deterrence exists between adversaries, large-scale conventional war and nuclear attack is sharply constrained or avoided. Where it does not, prolonged and devastating large-scale conventional war and nuclear attack becomes more likely.

The Indo-Pacific Strategic Gap

The Indo-Pacific currently relies on a patchwork of bilateral extended deterrence arrangements centered primarily on Washington. These remain essential, but they are increasingly strained or at risk of being fractured by China.

China’s expanding nuclear arsenal complicates escalation management. A larger and more survivable force reduces the credibility of assumptions that escalation will remain controlled or asymmetrical. Meanwhile, the region contains multiple flashpoints, including Taiwan, the South China Sea, the Korean Peninsula, and the India–China border where conventional conflict could rapidly climb the escalation ladder.

Frameworks like AUKUS and the Quad strengthen capabilities and coordination, while the proposed Pacific Defense Pact aims to guarantee that the U.S. and its allies can act in concert during crises or conflicts. But they are not structured as nuclear deterrence mechanisms. They do not institutionalize shared nuclear declaratory policy, crisis consultation at the strategic level, or joint planning for high-end escalation management. A nuclear alliance would fill that gap.

Beyond a Pacific Defense Pact

A Pacific Defense Pact, as envisioned in conventional terms, strengthens interoperability and signals unity. But without an explicit nuclear dimension, it leaves ambiguity at the highest rung of escalation. That ambiguity can invite miscalculation.

A nuclear alliance would not broaden commitments; it would sharpen them. It would: (1) establish shared declaratory policy on deterrence of large-scale war and nuclear attack, (2) institutionalize strategic consultation mechanisms during crises, (3) coordinate planning to ensure credible escalation management, and (4) reinforce extended deterrence while discouraging independent nuclear proliferation.

Importantly, such an alliance need not require additional states to acquire nuclear weapons. Like NATO, it could rely on extended deterrence commitments and nuclear-sharing with structured burden-sharing and planning arrangements. Nuclear forces may remain nationally controlled, but alliance cohesion amplifies deterrent credibility. 

Clarity as Stability

The objective is not confrontation. It is clarity. By defining a narrow and explicit threshold—large-scale conventional war or nuclear attack—the alliance reduces the risk of catastrophic miscalculation. It signals to potential aggressors that existential aggression will trigger unified strategic consequences.

Simultaneously, it reassures members that lower-level competition will not automatically escalate to nuclear commitments. This dual clarity strengthens deterrence at the top end and stabilizes politics at the lower end.

A Necessary Evolution

The Indo-Pacific is now the central arena of 21st-century strategic competition. Nuclear modernization is accelerating. Multi-nuclear dynamics are emerging. Escalation timelines are compressing.

History shows that nuclear weapons, and when embedded within credible alliance structures, deter catastrophic war. They prevent large-scale conventional war and nuclear attacks not because they are desirable tools of war, but because they impose unacceptable costs on those who contemplate it.

A Pacific Defense Pact is a step forward, but in the current strategic environment, it is not enough. To deter large-scale conventional war and nuclear attack in the Indo-Pacific, the region must move beyond a Pacific Defense Pact. It must build a nuclear alliance.

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: Why the Indo-Pacific Requires a Nuclear Alliance was originally published on Global Security Review.