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.

A decade ago, Paul Bracken warned of such possibilities in his book, The Second Nuclear Age. Because deterrence theory went out of vogue for so long in the West, analysts are now woefully unprepared to think about these challenges and their implications. Today, all possible threats to our Western notions of peace and stability have been jumbled into one giant intellectual recycling bin of deterrence theory. It is time to talk much more seriously about (1) the role of nuclear weapons in deterrence and (2) the role of nuclear deterrence in a new era of nuclear disorder in the Asia-Pacific.

Nuclear weapons play a unique and unprecedented role in how nations think about geopolitical order. They have fundamentally altered how countries think about alliances and the nature of international order. William Walker wrote about the establishment, in the late 1960s, of a nuclear order based on managed systems of deterrence and abstinence. The former was a system “whereby a recognized set of states would continue using nuclear weapons to prevent war and maintain stability, but in a manner that was increasingly controlled and rule-bound,” and in which there was a degree of familiarity in essentially dyadic deterrence relationships.

Nuclear abstinence consisted of a system “whereby other states give up sovereign rights to develop, hold, and use such weapons in return for economic, security, and other benefits,” concomitantly with the provision of nuclear umbrellas and a stable Nuclear Non-proliferation Treaty (NPT). It is a system whereby not only the possession, but also the use of nuclear weapons is controlled. According to Walker, the stability and robustness of these two systems would provide the rationale for many states in the international system to abstain from acquiring weapons and for states to rely on the US for their national survival.

There are several elements that gradually developed after the second world war that characterized this nuclear order—dissuading countries from developing nuclear weapons. First, the number of nuclear weapon states is relatively small. Second, nuclear weapons are no longer considered merely bigger and better conventional weapons. Third, there are strong norms against possession and the use of nuclear weapons. Fourth, there are no direct and immediate military threats to US allies. Fifth, war between major powers is relatively unlikely.

This and the prospects for nuclear proliferation are relatively limited. The Nuclear Non-proliferation Treaty (NPT) proposed in the late 1960s eventually attract more and more states, thus contributing to a norm against nuclear proliferation. It also contributed to nuclear and conventional arms control as concepts and policies in the international community. The world was able to more easily navigate crises and confrontations as thinking evolved about strategic theory and concepts and their application to real world politics and diplomacy.

The international (nuclear) order held together. It is now slowly eroding. China is modernizing its conventional and nuclear forces, all while growing increasingly bellicose and regularly threatening to invade Taiwan.

Russia annexed Crimea in 2014. The West did nothing and never imagined this would be followed by a full-scale invasion eight years later—with regular Russian threats to use nuclear weapons.

Now, Australian academic Peter Layton is writing about “this nuclear threat business.” Until recently, this behavior was reserved for rogue states like North Korea. Such behavior was beneath great powers such as Russia and the United States. Not only does the West have to think about deterrence in a multipolar setting, but it must face nuclear dictators.

Nuclear arsenals in Asia are also expanding. From China’s rapid nuclear expansion to questions about the future of Pakistan’s nuclear posture, the future is uncertain. There are renewed questions about the future of South Korea and nuclear weapons.

Arms control is also breaking down. Much to the chagrin of arms control careerists, who argue for unilateral, bilateral, and trilateral nuclear arms control as a public good sui generis, arms control is not carrying the day. Bereft of the intellectual foundations of deterrence that guided impressive negotiations in SALT I and II, and even START I, discussing nuclear strategy is now taboo in the West.

The nuclear order that existed during the Cold War and the post–Cold War peace dividend, especially in the Asia-Pacific, is eroding rapidly. For many nuclear historians, this trend is not new. Now is the time to grieve the loss of the utopian dream and think seriously about how to navigate this new era of disorder and the role of nuclear weapons in deterring war and promoting peace.

Christine Leah, PhD, is a Fellow at the National Institute for Deterrence Studies. Views expressed in this article are the author’s own. 

Nuclear Order and Disorder in the Asia-Pacific was originally published on Global Security Review.