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.

There is a comforting fiction at the heart of much contemporary strategic thinking: conventional military capabilities can substitute for nuclear deterrence without requiring the same political will. It is a neat idea—reassuring, technologically optimistic, and politically convenient. It is also dangerously wrong.

Deterrence does not reside in platforms, precision, or posture. It resides in belief—specifically, the adversary’s belief that you are both capable of inflicting costs and willing to do so. Strip away that second element, and deterrence collapses into theater.

This is the central problem confronting Australia and its allies as they navigate a rapidly shifting Indo-Pacific security environment. As nuclear risks grow, particularly with China’s expanding arsenal, there has been a noticeable intellectual pivot toward elevating conventional capabilities as a more “usable,” credible, and politically palatable form of deterrence. Long-range strike, autonomous systems, undersea warfare, and advanced ISR are all presented as tools that can impose meaningful costs without crossing the nuclear threshold.

However, this argument only holds if those tools are used. Too often, the debate stops at capability acquisition. Billions are spent, platforms are announced, doctrines are drafted. Yet, there is a conspicuous silence when it comes to the harder question: under what circumstances would Australia employ these capabilities in anger? What thresholds trigger their use? What risks are we prepared to accept in doing so?

Without clear answers, the signal sent to adversaries is not strength, but hesitation. Consider the logic from the perspective of a competitor. If Australia invests heavily in long-range strike but avoids articulating when it would employ it, an adversary may conclude that those capabilities are politically constrained. If grey-zone coercion, such as the deployment of sea mines, harassment of maritime assets, or interference with undersea infrastructure, does not elicit a forceful response, then the lesson learned is not deterrence, but permissiveness.

In this sense, ambiguity is not always stabilizing. It can just as easily invite probing. The uncomfortable reality is that conventional deterrence demands a level of resolve that many policymakers are reluctant to acknowledge. Unlike nuclear weapons, whose very horror lends them a paradoxical clarity, conventional forces sit in a murkier space. They are more usable, but precisely for that reason, credibility hinges on demonstrated willingness.

A missile that will is restricted from use is not a deterrent. A submarine that will not be deployed into contested waters does not shape adversary behavior. A cyber capability that remains permanently in reserve does not impose costs. Deterrence, in the conventional domain, is performative. It must be signaled, exercised, and at times demonstrated.

This does not mean recklessness or a rush to escalation. It means recognizing that deterrence is not cost-free. If the objective is to prevent adversary action, then one must be prepared to act before the situation becomes intolerable. Waiting until costs are imposed on you, economically, militarily, or politically undermines the very logic of deterrence. This is where much of the current discourse falls short. There is a tendency to treat conventional capabilities as inherently stabilizing, as though their mere existence alters adversary calculations. But capabilities without credible intent are inert. Worse, they can create a false sense of security, masking the erosion of deterrence beneath a veneer of preparedness.

The challenge is particularly acute for middle powers like Australia, which rely heavily on alliances and extended deterrence. As questions grow around the credibility of U.S. nuclear guarantees, especially in a more contested and multipolar environment, there is an understandable desire to bolster national self-reliance through conventional means. This is a sensible objective. But it cannot be achieved through hardware alone.

If conventional forces are to serve as a substitute or even a supplement to nuclear deterrence, then they must be embedded within a clear framework of political resolve. This requires more than capability development. It requires declaratory policy, strategic signaling, and a willingness to accept escalation risks.

For example, if the laying of sea mines in Australian waters is deemed unacceptable, then that must be stated clearly and backed by a credible commitment to respond with force if necessary. Anything less invites incremental encroachment. Over time, such encroachment normalizes behaviors that would once have been considered intolerable.

History offers ample evidence of this dynamic. Deterrence erodes not in dramatic moments, but through a series of small, unchallenged actions that cumulatively shift the baseline of what is acceptable. By the time a clear red line is crossed, it is often too late as the adversary has already recalibrated expectations.

The solution is not to abandon conventional deterrence, but to take it seriously. This means confronting uncomfortable questions. Are we prepared to use long-range strike capabilities against an adversary’s military assets in the initial stages of a crisis? Would we target grey-zone actors operating below the threshold of armed conflict? How do we signal our intentions without triggering the very escalation we seek to avoid? There are no easy answers, but avoiding the questions altogether is not a strategy, it is an abdication.

Ultimately, deterrence is about shaping perceptions. It is about convincing an adversary that the costs of action will outweigh the benefits. This cannot be achieved through ambiguity alone, nor through capability acquisition in isolation. It requires a coherent integration of means, messaging, and above all else, will.

If policymakers are unwilling to countenance the use of conventional force, then they should be honest about the implications. In such a scenario, conventional capabilities do not replace nuclear deterrence; they merely decorate its absence.

The risk is not just strategic failure, but strategic surprise. An adversary that perceives a gap between capability and intent will exploit it; once that perception is formed, it is exceedingly difficult to reverse.

Deterrence, in the end, is a test of credibility and resolve. It is not measured by what you possess, but by what an adversary believes you will do. In strategic competition, credibility is not claimed; it is proven and without resolve, deterrence is nothing at all.

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.

Deterrence Without Resolve Is No Deterrence at All 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.