The Unasked Question
Australia's discussion of deterrence has grown, yet one crucial topic remains noticeably absent.
Australia is spending $368 billion on nuclear-propelled submarines while refusing to discuss anything else nuclear—power, weapons, or strategy.
The government treats nuclear propulsion as a hermetically sealed engineering question, divorced from the strategic context that makes it necessary. AUKUS has been allowed to occupy the entire nuclear conversation—and thereby to prevent one.
But if US extended deterrence is becoming conditional—as seems the case, given both the US National Security Strategy and National Defense Strategy, and President Trump’s inconsistent behaviour towards allies—the question of what comes next cannot remain unasked.
American Aversion
The United States has pursued policies of non-proliferation for over 70 years1. Its strategy of inhibition extends to friendlies; it sees friendly proliferation as a quantitative problem—more fingers on triggers, more risk.
But the real question is qualitative, not quantitative: would a new entrant be a responsible custodian?
The relevant metric here is the Menzies test2: is a proliferator reluctant to resort to actual use because they sufficiently understand the costs? From that perspective, both South Korea and Japan look very different from North Korea or Iran3.
Proliferation isn’t a linear addition of risk. The system’s stability depends on the character of its nodes, the feedback loops between them, and the coupling between conventional and nuclear domains.
A responsible proliferator in a tightly coupled alliance may reduce instability; an irresponsible one amplifies it. In the new environment, the Americans are reasoning about the wrong variable.
Australia’s sealed window
Australia’s Overton window for thinking about a future indigenous nuclear capability slammed shut in the early 1970s. Australia eschewed nuclear proliferation, signing the Non-Proliferation Treaty on 27 February 1970, and ratified it on 23 January 1973. Nixon’s China opening forced a rethink of Australian foreign policy, shifting China from Communist menace to diplomatic opportunity and allowing Gough Whitlam’s earlier visit to be cast as visionary rather than reckless. Australia’s position on nuclear weapons has barely moved since.
Politicians no longer advocate for nuclear weapons, or even a serious realpolitik discussion about nuclear matters. Social media discourse is anonymous. Consequently, what debate exists is less a debate than scattered signals from the fringe.
Yet Australia has a conflicted nuclear identity, not a pacifist one. It never fully rejected nuclear weapons in defence of vital interests—it simply delegated the nuclear question to Washington and stopped thinking about it.
That delegation was rational when American commitment when to its allies seemed more credible. It is not rational now.
The AUKUS-driven, and climate-driven, shift in public attitudes toward nuclear power is worth noting as evidence that the window can move—and that the enablers (growing acceptance of deterrence as a concept, long-range delivery systems) are accumulating beneath the surface of public discourse. The Overton window may be starting to ease open.
The alliance cohesion problem
All of which raises the genuinely hard analytical question: how does friendly proliferation interact with extended deterrence?
The exposed ally reaches for nuclear options sooner than the guarantor. Triggers may vary. Targeting strategies may diverge. The South Korean Nuclear Consultative Group and Japan’s Extended Deterrence Dialogue are attempts to manage this tension—but they presuppose American reliability, which is precisely what is in doubt.
For Australia, the question is sharper still: it has no equivalent consultative mechanism4, no nuclear planning dialogue, and no institutional apparatus for thinking about these questions. It is a passive consumer of deterrence5.
The question Canberra won’t ask
During her 2023 National Press Club speech, Foreign Minister Penny Wong spoke of the desire to hold more instruments of deterrence in Australian hands.
‘We are investing in our national power, not just to guard against regional contest, but to shape and influence it to advance our national and shared interests.
We are doing this by creating deterrence, with major military investments in future capability, including through the AUKUS partnership.’
That was reinforced during her 2024 National Security College speech:
‘As recognised in the Defence Strategic Review, credible deterrence requires using all levers of statecraft to create an unacceptably high cost for any potential adversary…. Deputy Prime Minister Richard Marles made this point last week: that deterring conflict in today’s environment requires a new approach – one that harnesses all elements of our national power.’
Defence Minister Marles has made similar statements, for example, at the Center for Strategic and International Studies in 2022:
‘In addition to AUKUS, we need to continue the ambitious trajectory of our force posture cooperation, drawing on Australia’s strategic geography and our industrial base to maximise deterrence and reduce the risk of conflict.’
And at the opening of the Seoul Defence Dialogue, in 2023:
‘Because for Australia deterrence involves all aspect of statecraft: from increasing our defence capability, to non-military elements that disincentivise conflict and reassure states that they have options to seek their strategic goals within agreed rules, standards and laws, where sovereignty is respected.’
Take these statements seriously and follow them to their logical conclusion:
if deterrence requires shaping an adversary’s thinking,
and the adversary is nuclear-armed with substantial conventional forces,
then what instruments does a medium-sized conventionally-armed power actually possess that would do the work?
The answer is uncomfortable — which is precisely why the question must be asked.
A country which cannot even discuss the question is a country that has outsourced its strategic future to assumptions it has not tested.
Francis J Gavin, “Strategies of inhibition: US grand strategy, the nuclear revolution, and nonproliferation,” International Security 40, no. 1 (2015).
R G Menzies (1957) Ministerial Statement on Defence, 19 September 1957, Hansard, no. 38, p797.
One does wonder what Menzies would make of the Trump Administration.
Nuclear matters have been bundled with others in the bilaterial Australia-US Defence Policy talks, held at the (Australian) First Assistant Secretary level.
Perhaps disturbingly, the Australian government sees the value of extended deterrence less as a guarantor of Australia’s own security, and more as a hedge against nuclear proliferation. Defence Minister Marles, Shangri-La, 2025, the only mention of extended deterrence able to be found by the Defence or Foreign Minister: ‘All these actions risk sparking new proliferation cycles in both Europe and Asia, jeopardising US extended nuclear deterrence arrangements: a critical if under-sung asset in the fight against nuclear proliferation.’
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