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.

Hypersonic weapons, capable of exceeding Mach 5 with unpredictable flight paths, shatter the bedrock principles of conventional missile defense. Their ability to glide and maneuver within the atmosphere allows them to evade radar detection and interceptor systems, compressing warning times to mere minutes. This drastic reduction in reaction time amplifies the risk of miscalculations and accidental escalation, particularly in moments of crisis.

The global balance of power is being fundamentally altered, not merely adjusted, by the aggressive pursuit of maneuverable hypersonic weapon capabilities. China’s DF-17 hypersonic missile, coupled with its reported testing of a fractional orbital bombardment system (FOBS) with a hypersonic payload, demonstrates a clear intent to achieve global strike capabilities with minimal warning. Russia’s deployment of the Avangard HGV on its SS-19 intercontinental ballistic missiles and the operational status of the Zircon hypersonic anti-ship missile further highlight the growing proliferation of these advanced weapons. North Korea’s claim of successful hypersonic missile tests, while requiring verification, signal a potential integration of these weapons into its theater nuclear strategy, adding another layer of complexity to regional security.

The inherent capacity of maneuverable hypersonic weapons to render existing missile defense systems obsolete signifies not just a technological leap, but a deliberate dismantling of established strategic certainties. The unpredictability of their flight paths and the compression of warning times do not just complicate defense planning; they erode the very foundation of strategic stability, where deterrence relies on the certainty of retaliation. The potential for these weapons to carry both conventional and nuclear payloads does not just increase their versatility; it blurs the lines between conventional and nuclear conflict, creating a perilous ambiguity that heightens the risk of miscalculation.

The ability to strike targets with minimal warning does not just enhance offensive capabilities; it creates a coercive tool, enabling states to exert pressure and achieve strategic objectives without resorting to large-scale conventional warfare. The potential for hypersonic weapons to be deployed in a first-strike role does not just raise concerns about escalation; it fundamentally alters the calculus of deterrence, where the threat of retaliation may no longer be sufficient to prevent aggression.

To counter this burgeoning vulnerability, the United States must not merely react, but fundamentally redefine its strategic posture, acknowledging that piecemeal technological solutions are insufficient to address the profound shift hypersonic weapons impose on the security landscape. The rapid development of the glide phase interceptor (GPI) and space-based tracking systems is not just about enhancing missile defense; it is about restoring a sense of strategic stability, reassuring allies and deterring potential adversaries. The expansion of conventional hypersonic programs, such as the AGM-183 ARRW, conventional prompt strike, and the long-range hypersonic weapon, is not just about developing counterforce capabilities; it is about demonstrating a commitment to maintaining a credible deterrent, signaling to potential adversaries that aggression will be met with a swift and decisive response. The integration of hypersonic weapons into existing military doctrines does not just require tactical adjustments; it demands a fundamental reevaluation of strategic thinking, adapting to a new era of high-speed warfare.

The international community’s response to hypersonic weapons must not be limited to national defense initiatives; it must include a concerted effort to promote arms control and transparency. The absence of clear international norms and regulations regarding hypersonic weapons does not just create uncertainty; it fosters a climate of strategic competition, where states are incentivized to develop and deploy these weapons without restraint. The development of transparency and confidence-building measures is not just about reducing the risk of miscalculation; it is about building a foundation for strategic stability, where states can engage in dialogue and cooperation to mitigate the risks posed by these advanced weapons.

Hypersonic weapons represent a paradigm shift in military technology, fundamentally questioning if the world is entering a new era of vulnerability, undermining the foundations of traditional missile defense and reshaping the strategic landscape. Addressing this challenge requires a comprehensive approach that combines technological innovation, strategic adaptation, and international cooperation. Only through a concerted effort can the international community hope to mitigate the risks posed by hypersonic weapons and ensure a more stable and secure future.

Brandon Toliver, PhD, serves on the A4 staff of Headquarters Air Force. The views expressed are those of the author and do not reflect the official guidance or position of the United States government, the Department of Defense, the United States Air Force, or the United States Space Force.

Hypersonic Weapons: Are We Entering a New Era of Vulnerability? was originally published on Global Security Review.