In their recent ASPI paper, Paul Dibb and Richard Brabin-Smith suggested that government advisers need to ‘revisit the question of capability and warning time’ ^[1] based on the levels of military force Australia could face at short notice, particularly from China. The Pentagon’s 2017 report to Congress, Military and security developments involving the People’s Republic of China ^[2], provides a good insight into the issues Australian officials should be contemplating.

The prospect of a conventional war between China and the US ^[3] is frightening enough, but the thought of Australia confronting China alone brings on despair. That this might require a ‘capacity to engage in high-intensity conflict in our own defence—in a way that we haven’t previously had to consider’ is an understatement.

Strategic policy is plagued by the ‘plausibility of multiple alternative scenarios’ problem. Whether deriving foreign policy objectives, shaping defence capability investment, establishing force readiness levels or deploying combat forces, the government has to commit to the notion that some future scenarios are more plausible than others.

The 1987 Defence White Paper ^[4] determined that it ‘is possible to indicate the principal contingencies that must shape Australia’s defence planning’. In particular, ‘force structure planning’ should ensure Australia’s capacity to respond to those contingencies. The three levels of ‘credible’ contingencies—low level, escalated low level and more substantial—also informed judgements about logistics, sustainment, basing and industry policy. That led to plausible scenarios with an emphasis on northern Australia. The intellectual power of the levels of contingency was generated by the concept of warning time ^[5].

However, the 1987 white paper had not anticipated the end of the Cold War, which reconfigured fundamentally the global strategic situation. Cold War superpower competition was a zero-sum game and Australia could be confident of US support in the remote possibility of a Soviet threat. That left Australian planners to deal with credible lower-level contingencies.

But for warning time, the end of the Cold War meant that ‘the concept and its systematic force structure guidance … disappeared from our defence white papers ^[6]’ and ‘the 1987 rationale disappeared along with the calculations ^[7]’. The 1994 white paper ^[8] observed that ‘previously, our defence planning has been able to assume a degree of predictability in our strategic circumstances’, and that no longer existed.

China would need to have a very serious dispute with Australia to take military action, a dispute that couldn’t be resolved without military action. China would need to have a clear and crucial strategic or national objective. Such a dispute isn’t currently in prospect, but the quirks of international politics don’t exclude the rapid appearance of one. The recent differences over trade and climate issues between allies is evidence of how quickly the ground can shift.

In the event of a dispute so serious that it made military aggression unavoidable, the most plausible scenario is one where China immediately threatened or targeted cities or infrastructure in southeastern Australia. Even if an attack on Australia was a diversion in the context of a wider East Asian war, Chinese forces would most likely target strategically significant assets in the southeast. A major assault in the north of Australia would make little strategic sense.

The further out into the future this scenario is projected, the more difficult becomes any plausible effective Australian response. China is growing its blue-water navy and will continue to do so, providing it with significant reach and stand-off capability. Successful defence of the southeast of Australia in decades to come seems progressively more improbable.

Against an adversary like China, the notion of warning time and the associated concept of an expansion base for the ADF seem obsolete. As the Pentagon report emphasises, China’s military capabilities are already growing at rate that Australia will never be able to match. No matter how much warning time Australia had of an attack, it wouldn’t be able to make adjustments that would materially alter the increasing deficit in relative military power of the two states.

On the contrary. Australia will progressively fall further behind China. China’s defence budget is predicted to reach US$260 billion by 2020, compared to Australia’s 2017–18 defence budget ^[9] of US$25.6 billion. In addition, China’s massive investment in science and technology ^[10] is geared to producing a military force that is not just large, but at the absolute cutting edge of technology. China is among the world leaders in robotics ^[11], artificial intelligence ^[12] and space technology ^[13], and has accorded high priority to the application of science to capability.

That doesn’t mean that the ADF shouldn’t be as modern, capable and prepared as Australia can afford. It does mean that no matter how much or how little warning time Australia has to plan, within a decade or so no expansion base will be sufficient to defend effectively vital Australian assets from a concerted Chinese assault. The defence planning and strategic concepts of the Cold War era have little relevance today.

On the one hand, of course, no scenario is plausible where, within current planning horizons, the ADF would confront China except in company with the US and in the context of the alliance. On the other, the strategic reality is that the future of Australia is entwined with China’s and needs to be part of it. Responding to China will not be primarily a defence matter. It can only be a matter for foreign policy and diplomacy.