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.

As a strategy, MAD was considered but jettisoned by the United States 65 years ago. For example, President John F. Kennedy noted, “Above all, while defending our own vital interests, nuclear powers must avert those confrontations which bring an adversary to a choice of either a humiliating retreat or a nuclear war. To adopt that kind of course in the nuclear age would be evidence only of the bankruptcy of our policy, or of a collective death-wish for the world.” Kennedy succeeded in adopting a strategy short of all-out retaliation that came to be known as “flexible response,” which, in 1974, was fully developed by James Schlesinger and eventually codified in Presidential Defense Directive 59.

Whether the United States has 10,000 or 1,500 strategic nuclear weapons, American forces were designed to have a secure retaliatory capability at any level of conflict. The objective was to end any conflict as soon as possible and at the lowest level of destruction. The American objective was not to burn an adversary’s cities to the ground. American deterrence strategy was to hold at risk what the adversary valued most.

Critics of current deterrence strategy assume that no nuclear-armed adversary of the United States believes in “fighting” a nuclear war. So, the US should drop its long-held deterrence strategy and go back to MAD or something like it. At the same time, many of these critics join nuclear abolitionists to support nuclear weapons but only to deter, not engage, in warfighting. If conflict breaks out and these weapons will not be used in retaliation, then nuclear forces are off the table and reduced to a bluff.

The mistaken notion that the US has a MAD strategy plays into the hands of Russia and China. These two nations both seek to escalate or threaten to escalate in a crisis or conflict with the limited use of nuclear weapons. The objective is to get the United States to stand down and not come to the defense of her allies, a restraint to give Russia and China a strategic advantage.

Unfortunately, much of the current commentary on nuclear threats still assumes the US and its adversaries maintain a mutually assured destruction strategy as the best means to avoid any use of nuclear weapons. Annie Jacobson’s recent book, On Nuclear War: A Scenario, describes a mutually assured destruction strategy, which she assumes the US maintains, as simply MAD or crazy. She posits that any initial use of nuclear weapons would almost automatically result in the all-out use of such weapons, leading to nuclear winter and killing billions. As such, she calls for the entirety of American nuclear deterrence to be jettisoned.

Being in the deterrence business, it is important for Congress, the media, the executive decisionmakers in the military and Department of Defense to fully understand what deterrence, as practiced by the United States, entails and why it must be sustained.

To explain this requires a review of history and an understanding that adversaries of the United States and the West sought military advantage through enhanced nuclear weapons technology. Over time the challenge for the US to sustain deterrence changed. The Soviets sought to put nuclear weapons in space, then built a huge first-strike missile force, then deployed thousands of medium-range SS-20s to intimidate and split NATO, and, most recently, built a theater-strike capability to keep the United States and NATO from winning the war in Ukraine.

The US nuclear deterrent was never one size fits all and automatically fit for purpose. For example, the US and NATO faced a huge conventional military threat from the Soviet Union from the beginning of the Cold War on the plains of central Europe, a place called the Fulda Gap. The Soviet and Warsaw Pact tanks were not matched by American conventional forces. President Dwight D. Eisenhower did not wish to bankrupt the US treasury by building such a large and costly conventional military. The available alternative was to establish a nuclear umbrella over Europe, primarily aimed at Soviet tank armies. Thus, in the initial Cold War period, the US assumed a nuclear conflict would most probably grow out of an initial conventional war.

As technology improved, however, a threat emerged that could markedly change the correlation of forces between the United States and the USSR. The US still sought to deter a potential Soviet push into central Europe, but an additional threat was a potential Soviet pre-emptive first strike seeking to eliminate much of the American extended deterrent, followed up by a subsequent conventional invasion of Europe.

In 1963, the American strategic nuclear deterrent consisted of 6,000 nuclear warheads while the Russians had 600 warheads. As President Kennedy remarked, this strength, and particularly the newly deployed Minuteman missiles, were “my ace in the hole” that gave the United States the strategic advantage that peacefully ended the Cuban Missile Crisis.

However, by the time the next decade ended, the 1972 Strategic Arms Limitation Talks (SALT) “arms control” treaty process was implemented and the USSR largely caught up, deploying 7,800 warheads compared to the US force of 8,700 warheads. Most worrisome was the new Soviet land-based missile force of 3,000 warheads on highly accurate SS-18s—with the overall Soviet nuclear force projected to grow to over 24,000 warheads by 1993.

As Secretary of Defense Melvin Laird told Congress in 1974, “the Soviets are going for a first strike force and there is no doubt about it.” The SS-18 eventually held at risk the entirety of the US land-based intercontinental ballistic missile (ICBM) force. This was the only American deterrent force that was sufficiently accurate to target key Soviet leadership and military targets without requiring “city busting.”

The US stopped deploying land-based missiles at 1,050 and associated warheads at around 2,000—assuming the USSR would show equal restraint. But Moscow built a huge land-based ICBM force that could take out the nation’s Minuteman missiles, leaving the US without the ability to hold key Soviet assets at risk. This perceived imbalance was known as the “window of vulnerability” where the US faced the prospects of a Soviet-initiated first strike that would leave US leaders exactly where President Kennedy worried it would.

The US solved the strategic equation of the window of vulnerability, the Soviet empire collapsed, the US added the Trident II D-5 submarine-launched ballistic missile and Peacekeeper land-based ICBM, Soviet SS-20s were banned, and the Strategic Arms Reduction Treaty (START) arms control process brought Russian warheads down to under 2,000.

In April 1999, Russian President Boris Yeltsin, economically unable to rebuild a Soviet-era nuclear force, decreed that Moscow develop highly accurate, small, low-yield, battlefield nuclear weapons, which his successor, Vladimir Putin, did in earnest. As former Vice Chairman of the Joint Chiefs of Staff General John Hyten warned, these theater nuclear weapons were designed to “escalate to win” a conventional conflict or crisis between Moscow and Washington.

Putin thinks the US will not respond to the small-scale use of nuclear weapons because the US will not want to risk escalation and the possibility of strategic nuclear exchange. That is why Putin made exactly these threats over NATO’s intervention in the war against Ukraine.

Both Russia and China assume the relative weak theater nuclear forces the US maintains are now insufficient to match escalatory threats from Moscow and possibly Beijing. This point was emphasized by the 2023 Strategic Posture Commission report in laying out the opening of a new window of vulnerability.

The US is indeed now developing a greater theater nuclear deterrent to close the technology gap. However, simply adding to America’s conventional deterrent is not sufficient. As military leadership has repeatedly emphasized, if adversarial nuclear forces are introduced into a conventional conflict, the American advantage ceases. In short, conventional military leverage disappears.

The central tenets of mutually assured destruction no longer apply. MAD was jettisoned long ago. More importantly, America’s adversaries employ credible threats with the nuclear forces. New technology and expanding adversary arsenals are undermining the limited deterrent value of the American nuclear arsenal, a fact that must change if the United States seeks to ensure it does not find itself embroiled in a conflict where capitulation or Armageddon are the nation’s only options.

Peter Huessy is a Senior Fellow at the National Institute for Deterrence Studies.

Mutually Assured Destruction was originally published on Global Security Review.