Compared with the Rudd Government's 2009 Defence White Paper, which was criticised for what many viewed as its alarmist treatment of China's rise, the most recent White Paper, released in April this year, has become known for its considerably more relaxed take on the issue.

There may be good diplomatic and political reasons for this. Yet however much these concerns weighed on Canberra, one thing needs to be clear: there is no strategic basis for the newly optimistic assessment of China's rise. To the contrary, military developments in China since the late 2000s reveal a more ominous picture than many previously anticipated, or indeed than many within our defence and security establishment are today prepared to openly acknowledge. Over that period China's military build-up has entered a new phase, in parallel with the emergence of its increasingly assertive diplomacy and voracious intelligence collection.

This is an unfamiliar situation for Australia. For the first time since World War II, a major power in our region appears set to develop a full suite of military capabilities that could pose a direct military threat to Australia. And China could do so in the same or even less time than it would take to acquire countervailing capabilities.

That Chinese leaders regularly profess benign intentions is cold comfort. While an attack remains highly unlikely, prudent defence planning, because of the scale of risk it seeks to mitigate, is always based on capabilities. Capabilities take years or decades to develop, whereas intentions or behaviour can change overnight (and in China's case, they did so as recently as 2010, when its then conciliatory diplomatic style unexpectedly hardened).

Concerns among Australian defence planners about the direct threat posed by China's military power have long been tempered by two crucial considerations: the limited range of most of China's conventional forces and their strategically defensive orientation.

Even as decades of growth in China's military spending allowed it to amass more and better submarines, combat aircraft, missiles of all varieties, and surveillance systems, these have been stitched into a defensive strategy, what the Pentagon calls anti-access/area-denial (A2AD), essentially a muscular form of coastal defence. This approach is intended to make it impossible for US forces, primarily aircraft carriers, to operate along China's maritime periphery in a conflict, denying the US military control of the air and sea and hence the ability to conduct the full-range range of follow-on operations.

This strategy still entails risks for Australia. But China's A2AD strategy has long acted as an implicit source of reassurance, since it precludes China from undertaking activities relating to the most serious threats, a direct attack on our continent or a lodgement in the islands to our north.

China's military has never been structured for tasks associated with the sustained projection of power or acquiring territory from the sea. Without aircraft carriers, China cannot control the air beyond the range of its land-based aircraft, and lacking a flotilla comprised of destroyers, frigates and nuclear-powered submarines, it could not reliably clear threats on, above or beneath the sea to ensure the safe transit of men or materiel over long distances.

Today, all aspects of that situation are changing.

As its A2AD strategy matures, China's focus has turned increasingly toward the kind of naval fleet that will give it punching power further afield, including into the seas north of Australia. At the heart of this effort is China's first aircraft carrier, the Liaoning.

Vulnerable to detection and lacking a launch-catapult that would extend the range and payload of its aircraft, the Liaoning is not by itself a formidable military capability. However, this belies its broader significance. According to Australia's Defence Intelligence Organisation, 'China will probably build multiple aircraft carriers over the next decade.' The Liaoning thus marks the beginning of a more earnest phase in China's blue-water experiment.

Beyond the ship's role as a status symbol and source of national pride, it will begin familiarising Chinese strategists, sailors and pilots with the complexity of carrier operations. Some approaches will be discarded; others will be absorbed into the design and operation of successive carriers, reducing cost and lead-times and paving the way for a more potent capability in future.

Meanwhile, China's blue-water ambitions continue to materialise in less conspicuous ways. After lengthy experimentation, serial production has begun on a new class of destroyers. These can function as escorts, providing carriers with a protective screen against enemy aircraft and, to a lesser extent, submarines. China has also begun redressing longstanding weaknesses in its capacity for early warning, command and control, and at-sea replenishment, all important components in the portfolio of unglamorous capabilities necessary to support long-range maritime operations.

Taken together, these developments point to three worrying conclusions, with deep implications for Australian strategic policy.

First, China is in the early stages of building a genuine blue-water navy. The advent of costly support capabilities with little prestige value suggests the fleet is not intended purely as a status symbol, as many had previously assumed (myself included). Nor can we confidently dismiss it as just 'boys with their toys'. The scale of investment appears to exceed that of a side-project designed to satisfy any institutional preferences the PLA Navy harbours for large surface combatants.

That just leaves the simple explanation. From a defence planning perspective, China's blue-water ambitions should be interpreted as a subset of its geopolitical ambitions, and taken just as seriously. Like every great power before it, China wants to keep open the option of exerting a more monopolistic influence over the region it inhabits. To this end, Beijing recognises power-projection capabilities as a necessary if not sufficient prerequisite.

Second, the operation of China's fleet for such purposes presupposes sharper limits on American military power, and particularly on those elements of American power that would most imperil Chinese ships, namely US submarines. That Chinese plans are moving ahead anyway suggests that Beijing conceives of circumstances in which it could either overcome American resistance or else avoid it altogether. It would, after all, be unwise to assume that China is building capabilities it believes could never be used. Whether this means defeating the US militarily or deterring it, or else waiting for some form of US retrenchment, remains unclear.

The disturbing thing for Australia is this: Where Canberra has gambled on the more-or-less permanent military superiority of our American ally, Beijing has, with its incipient fleet, placed a sizeable wager on the exact opposite outcome. Both can't be right.

Finally, China is making another bet: that the smaller countries in the region, including Australia, will neither independently acquire the A2AD capabilities necessary to offset the threat posed by the Chinese fleet before it becomes operational, nor form a sufficiently cohesive group that could aggregate its military resources to do so. Given the enduring anaemia of strategic cooperation in Southeast Asia and beyond, and considering that Australia has itself prioritised building a lumbering blue-water navy at the expense of more appropriate A2AD capabilities, that's not looking like such a bad bet.