Introduction

Russia’s recent deployment of a conventionally armed, diesel-powered submarine to Indonesia should not be dismissed as routine naval activity. It is a calculated strategic signal. One that highlights a growing challenge for Australia and calls into question the resilience of U.S. extended deterrence in the Indo-Pacific. While such deployments fall below the nuclear threshold, they reveal an emerging approach to strategic competition. The use of advanced conventional capabilities can undermine the systems that enable nuclear deterrence.

At the center of this challenge is the vulnerability of U.S. nuclear command, control, and communications (NC3) architecture. Facilities in Australia, including Pine Gap and Naval Communication Station Harold E. Holt, are integral to this architecture. They support early warning, signals intelligence, and communications with nuclear forces. As such, they are not only strategic assets but also potential targets. Modern diesel-electric submarines—quiet, survivable, and increasingly capable—can operate in Australia’s northern approaches and threaten these critical nodes with precision strike options or intelligence-gathering missions that enable future disruption.

The Gray Zone Effect

This development reflects a broader shift in adversary strategy. Rather than relying on overt nuclear coercion, states such as Russia are exploring how to achieve strategic effects through conventional means. By targeting NC3 infrastructure using submarines, cyber operations, or long-range precision strike, adversaries can degrade the credibility of nuclear deterrence without crossing the nuclear threshold. This approach exploits the grey zone between peace and war, complicates escalation dynamics, and introduces ambiguity into alliance responses. It is not escalation dominance in the traditional sense, but escalation manipulation, and shaping the environment so that nuclear deterrence becomes less certain, less credible, and therefore less effective.

Recent Chinese naval activity reinforces this concern. The PLA Navy’s circumnavigation of Australia should not be viewed as routine presence or symbolic signaling alone. Rather, it demonstrates an emerging capacity to operate persistently along Australia’s littoral approaches and key maritime choke points—areas proximate to critical infrastructure that underpins U.S. and allied NC3. Such operations enable the mapping of undersea terrain, surveillance of communication pathways, and potential identification of vulnerabilities in systems such as subsea cables and relay nodes. In a crisis, these capabilities could be leveraged to conduct limited, deniable disruption of NC3 functions that degrade communication, delay decision-making, and complicate alliance coordination without crossing the threshold of armed attacks. In this sense, China’s activity mirrors and reinforces the broader trend: the use of conventional means to hold at risk the foundations of nuclear deterrence.

For Australia, the implications are significant. The traditional model of U.S. extended deterrence, anchored in the threat of nuclear retaliation, assumes that nuclear forces remain survivable, communicable, and politically usable. However, if NC3 systems are degraded or disrupted, that assumption weakens. Deterrence begins to erode not because nuclear weapons are absent, but because their employment becomes uncertain or delayed. In such a scenario, adversaries may calculate that they can act with greater freedom at the conventional level, confident that escalation can be managed or avoided. 

Policy Recommendations

This evolving threat environment demands a recalibration of Australia’s defense and deterrence posture. Nuclear deterrence remains essential, but it is no longer sufficient on its own. It must be reinforced by a comprehensive strategy that integrates conventional resilience, grey-zone competition, and a more explicit recognition of the role nuclear forces play in underpinning deterrence across all domains.

First, Australia should prioritize the hardening and resilience of NC3-related infrastructure on its territory. This includes enhancing physical protection, investing in redundancy and dispersal, and strengthening cyber defenses. Facilities such as Pine Gap and Harold E. Holt must be able to operate under contested conditions, ensuring continuity of communication and decision-making even in the face of sustained disruption. This may also require the development of alternative communication pathways, including space-based and mobile systems. Resilience is not merely a defensive measure; it is a core component of deterrence, signaling to adversaries that attempts at degradation will not succeed.

Second, Australia must significantly expand its undersea surveillance and anti-submarine warfare (ASW) capabilities. The ability to detect, track, and, if necessary, neutralize hostile submarines in Australia’s maritime approaches is critical to protecting strategic infrastructure. Investments should focus on integrated undersea sensor networks, maritime patrol aircraft, autonomous systems, and closer operational integration with allies. A persistent and credible ASW posture will complicate adversary planning, increase operational risk, and reduce the feasibility of covert operations targeting NC3 nodes.

Third, Canberra should deepen strategic dialogue with Washington on the role of Australia within U.S. nuclear deterrence architecture. This dialogue must move beyond general assurances and address specific contingencies, including how attacks on NC3 infrastructure in Australia would be interpreted. Greater clarity around escalation thresholds, attribution challenges, and response options will reduce the risk of miscalculation and strengthen the credibility of extended deterrence. This should include regularized nuclear consultation mechanisms and scenario-based planning.

Fourth, Australia should take the lead in advocating for the development of an Indo-Pacific nuclear alliance. Such a framework that brings together the United States, Japan, South Korea, the Philippines, Papua New Guinea, and Australia, would formalize shared deterrence responsibilities and strengthen collective resolve. While politically sensitive, this arrangement could include elements of nuclear consultation, planning, and burden-sharing, similar in principle to NATO’s nuclear sharing arrangements. By distributing deterrence functions and signaling unity, such an alliance would complicate adversary calculations and reinforce the credibility of nuclear deterrence across the region.

Fifth, Australia must engage India more directly on the implications of Russian strategic behavior. As a key regional power with longstanding ties to Moscow, India occupies a unique diplomatic position. Canberra should clearly communicate its concerns regarding Russian military activities in the Indo-Pacific, including the risks posed to critical infrastructure and regional stability. In parallel, India should be encouraged to consider the broader consequences of a hypothetical Russian attack on Australia, not only for bilateral relations, but for its strategic partnerships with both the United States and Australia. This dialogue would not seek to force alignment, but to underscore the interconnected nature of regional security and the potential costs of strategic ambiguity.

Sixth, Australia should explore options to visibly anchor U.S. nuclear deterrence in the region. This necessitates a proactive approach to alliance integration. Mechanisms such as enhanced consultation, increased transparency around nuclear policy, and potential participation in nuclear planning arrangements could reinforce deterrence by demonstrating resolve and cohesion. Initiatives under AUKUS provide a foundation for this deeper integration and should be expanded to include broader deterrence considerations.

Seventh, Australian defense policy must explicitly recognize the interdependence of conventional and nuclear deterrence. Investments in long-range strike, cyber capabilities, and undersea warfare are essential, but they must be understood as part of a broader deterrence framework. These capabilities contribute to resilience and denial, but they are ultimately underpinned by the threat of escalation. Ensuring that this relationship is clearly articulated in strategy and doctrine will strengthen deterrence coherence and improve signaling to adversaries.

Finally, Australia must broaden its strategic focus to account for multiple nuclear-capable adversaries operating in the Indo-Pacific. While China remains the primary focus of defense planning, Russia’s increased presence in Southeast Asia underscores the need for a comprehensive approach. Strategic competition is no longer confined to a single actor or domain. It is multi-faceted, simultaneous, and increasingly coordinated. Australia’s deterrence posture must reflect this complexity.

Conclusion

The central lesson is clear. Deterrence in the 21st century cannot be treated as a layered system in which nuclear weapons sit passively at the top. Instead, nuclear deterrence must actively underpin and reinforce every level of conflict, including the conventional and grey-zone domains. Adversaries are increasingly seeking to exploit gaps between these layers, using conventional means to achieve strategic effects without triggering nuclear retaliation.

To respond to this challenge, Australia must take seriously the credibility of the nuclear deterrent on which it relies. This means investing in the resilience of critical systems, strengthening conventional capabilities, and engaging more deeply with allies and partners on the role of nuclear alliances and forces in regional security.

In an era defined by ambiguity and threshold management, the effectiveness of deterrence will depend on integration, clarity, and resolve. By advancing new nuclear alliance structures, deepening strategic dialogue, which includes India, and reinforcing both conventional and nuclear pillars of deterrence, Australia can ensure that sophisticated conventional threats do not undermine the stability of the broader strategic order.

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.

Silent Signals: Russian and Chinese Conventional Threats to NC3 and U.S. Extended Deterrence in Australia 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.

Yet, due to several factors including the American moratorium on testing destructive ASAT weapons, concerns of environmental sustainability, and increased use of grey-zone tactics by adversaries, inferential and non-kinetic ASATs may be the primary means with which conflict in outer space is waged in the immediate future. Thus, emphasizing potential negative impacts upon strategic deterrence for both nuclear and space arenas is essential.

Contrasted with kinetic physical ASATs, which are highly attributable, cause permanent damage, and simultaneously signal both capability and the political will of the aggressor, inferential ASATs are a broad categorization comprised of capabilities that do not create debris fields and are significantly less visible to third-party observers. This grouping, which encompasses directed energy, electromagnetic, radiofrequency, and cyber capabilities, does not strictly align with the traditional categorizations of kinetic physical and non-kinetic physical ASATs, and can include non-kinetic physical attacks.

For example, military-use electromagnetic pulse (EMP) weapons are categorized as non-kinetic physical attacks but may be categorized as “inferential” because they are rapid, invisible, and can affect damage with indirect contact with a satellite. Considering this proposed categorization, changing technological environment, and increased used of grey-zone tactics in the space domain, it is time to take a hard look at the underlying theories guiding national security strategies such as strategic-level deterrence; specifically, its tenants of credibility and signaling, which could be negatively impacted by the inferential attributes of new weapons systems.

Successful deterrence theory and practice is contingent upon (1) credible psychological impact upon the adversary; (2) communication of an attributable weapon capability, wherein the ability to visibly detect or identify the negative consequences of attack are clearly signaled; and (3) the political will to carry out such an attack if attacked by an aggressor. The proliferation of inferential ASAT capabilities significantly alters this cost-benefit calculus due to the difficulty of attributing their use in attacks.

Moreover, since conventional weapons capabilities evolved to include virtually undetectable forms of attack with little progress towards attribution, it is reasonable to conclude that the successful operationalization of deterrence against inferential ASATs will be difficult to achieve in outer space.

Credibility and Signaling

Generally, credibility is characterized as the effective communication (signal) to an adversary through deterrence posture, so as to compel the adversary to believe the utility of the planned attack, thereby, psychologically registering the attack as a sufficient threat. Since the value of signaling lies in the opponent’s perception, and because inferential capabilities engender difficulties in attribution, adversaries remain undeterred so long as the attack does not register as a threat.

Degradation of credibility occurs when signals are misinterpreted or misperceived, as well as if there are differing belief systems and intentional interference by the adversary. If present, these factors are likely to result in a weakened deterrence posture; this remains especially true when such signals are below the escalatory threshold of retaliatory response, as is the case with grey-zone tactics that employ inferential capabilities.

Proposed Solutions

A potential solution to the credibility and signaling problem in the space domain would be to bolster deterrence strategies with an integrative triad that combines special operations, cyber, and space force capabilities. While still largely in development, the triad could leverage space-based competencies such as space domain awareness, space forensics, dual-use spacecraft, proximity operations, or on-orbit servicing to fill the gap left open by weakened attribution capacity and to deter actions below the threshold of conflict without having to resort to kinetic-type ASAT.

The question here is whether such space-based capabilities, especially dual-use spacecraft, serve to deter or escalate conflict. In 2022, China’s Shijan-21 docked with a defunct Chinese satellite and towed it into a graveyard orbit. This not only demonstrated China’s technological advancement, but also its ability to conduct counter-space operations under the pretense of debris-removal operations. Such developments point to the trend of increased reliance on inferential capabilities by adversaries and negative implications of strategic-level deterrence in outer space.

In an explosive, technological growth environment, the non-demonstrable nature attributed to inferential ASATs are allowing an increasing number of non-state actors adverse to the United States to take self-motivated action in ways that hinder the successful application of deterrence strategies. While a deterrence triad can bolster credibility and signaling, inferential ASATs remain below the threshold for escalation, degrading the integrity and security of outer space systems over time. Thus, the salience for deterrence within this context in this discussion is not only meaningful for its theoretical applications, but also because its successful implementation implies that deterrence as a theory is highly adaptable, resilient, and will continue to remain relevant in formulation of the United States’ national space strategies going forward.

Kaili Ayers is a JD candidate at the University of Oregon School of Law and Law Clerk at the Space Court Foundation. The thoughts, opinions, and analysis presented here are her own and do not reflect the position of the University of Oregon or the Space Court Foundation.

Anti-Satellite Capabilities and American Options for Strategic Deterrence in Outer Space was originally published on Global Security Review.