The defence white paper released by Malcolm Turnbull on Thursday sets out a maritime strategy for defending Australia. The policy completes a shift in thinking about the best way to design and run a small military force with the task of defending a massive geographic area.

A generation ago Kim Beazley’s 1987 defence white paper set out a strategic plan much more narrowly conceived around defending the country in the so-called “air-sea gap” between Australia and the Indonesian archipelago.

Since then strategic events in our region and the increasing range and precision of modern weaponry mean that if Australia faces a direct threat we have no choice but to tackle it much farther away from our shores.

If an aggressor’s forces make it to Australia’s “sea-air gap” we will have already sustained a major strategic defeat.

This is why the overwhelming thrust of the new defence white paper is on building up strong maritime capabilities, buying an array of manned and unmanned aircraft, and long-range missiles.

The paper also points to new investment in ballistic missile defence and space surveillance to watch potential enemy movements on a vast battlefield.

It’s also why the white paper’s most important strategic defence interest, as it’s termed, is “to support the security of maritime Southeast Asia” and the South Pacific. Even more than previous white papers, the document stresses how Australia will boost military co-operation with Asian countries.

The aim is to sustain peace and make war less thinkable. But defence forces are designed to fight when peace is no longer possible and the new design of the Australian Defence Force is about taking the fight into maritime Southeast Asia.

All this points to the critical importance of the South China Sea and, no doubt, why Chinese diplomats reacted so quickly against the paper’s pointed reference to Beijing: “Australia is particularly concerned by the unprecedented pace and scale of China’s land reclamation activities.”

In early 2014, when Defence was gearing up to produce the white paper, China had only just started its massive island construction projects in the South China Sea. At that stage there were no military-grade runways on the islands, no missile batteries or air defence radars, fewer warship deployments and no squadron-size visits from Chinese combat aircraft.

In the time it took Australia to write a defence policy statement, China has transformed much of the South China Sea into a well-fortified bastion for the People’s Liberation Army and a string of paramilitary forces focused on denying access to the region for any other countries.

A central challenge the defence white paper presents to government is to work out precisely how it can respond to this Chinese action. A maritime-based defence strategy focused on Southeast Asia cannot avoid dealing with the South China Sea problem for long.

Longer term, the plans set out in the white paper will provide significantly stronger maritime warfare capabilities with an emphasis on being able to sink an opponent’s submarines and surface ships.

The long-awaited 12 “regionally superior” submarines will be the core of Australian military capability. Why 12? The reality is there never has been a precise strategic rationale for that number. Its political origin was in Kevin Rudd’s 2009 white paper. Twelve submarines had an appealing muscularity for Rudd and happily doubled the size of the current Collins fleet.

So much for the science of military force design. But 12 submarines actually delivers a powerful and important result, which is the capacity to have several boats at sea permanently at considerable distance from Australian shores.

This complicates the planning of any adversary thinking of doing harm to Australian interests and builds a stronger deterrent effect for Australian security.

Just as Australia is acquiring submarines, so too are many countries in the Indo-Pacific. The white paper announces rather breathlessly: “In the next 20 years, half the world’s submarines and at least half the world’s advanced combat aircraft will be operating in the region.” That’s true, but as our region encompasses the Indian and Pacific oceans, we are looking at about half the world anyway.

Increasingly, the Asia-Pacific half of the world is engaging in an arms race with a strong maritime flavour. The white paper says that a great deal of this growth in military power is a natural process of modernisation. But modernisation is substantially increasing the range, precision and hitting power of regional military forces.

China’s own projected military growth is enormous and it is clearly spurring countries as dispersed as India, Japan and the US to rethink their own military modernisation efforts.

The other Australian defence acquisitions announced in the white paper are designed to make sure the ADF can hold its own in a higher-technology, more lethal environment. The combination of surface ships, maritime patrol aircraft, remotely piloted vehicles and intelligence systems will produce a small but deadly force.

As a component of a larger coalition of forces or, indeed, as a standalone outfit, Defence will be able to operate as a powerful unit in the waters of Southeast Asia, the Pacific and Indian oceans.

As the Prime Minister said last week, this is an expensive but essential investment, aimed at preventing conflict by showing how effectively we can defend our interests.

This is the thinking around the design of a future defence force—key elements of which, like the submarines, won’t be in place for decades.

The more immediate challenge for Turnbull is to find a practical strategy that can help to counter China’s aggressive push for territory in the South China Sea.

The speed of China’s sovereignty grab is matched with a political strategy borrowed from Vladimir Putin’s playbook on display in the Crimea and eastern Ukraine.

In 2014 Putin’s approach to the Ukraine crisis was to make incremental gains using forces without Russian military insignia—the so-called “little green men”—staying below a threshold of action that would trigger a massive NATO response.

Beijing’s approach in the South China Sea has closely mirrored the Russians’ tactics. Initially it was fishing boats and “white hulled” non-PLA Navy ships that harassed the ships of other countries as they fished or transited the region.

China subsequently has aimed at keeping its actions below a threshold that would force the US to declare a red line and push back with a military response like a naval ship transit.

Washington’s approach hasn’t helped because it’s often stated reluctance to buy into sovereignty disputes over rocks and shoals only emboldened China to speed up its militarising of the region.

While Beijing was changing the facts on the ground its actions have been accompanied with the most brazen diplomatic denials about its intentions.

The defence white paper calls for countries “to be open and transparent about the end state purposes of land reclamation activities” in the South China Sea.

No one in Canberra’s national security community has the least doubt about China’s “end state purposes”. The need is for the government very quickly to make a stronger response.

A starting point should be for Australia to lead a strong diplomatic effort in Southeast Asia, developing a common statement that China should immediately withdraw its anti-aircraft missiles, radars and combat aircraft from Woody Island in the South China Sea.

Australia also should work pre-emptively to weaken any Chinese claim to declare an air defence identification zone. It’s highly likely that Beijing will unilaterally announce an ADIZ around the Paracel Islands, south of its major submarine base on Hainan Island.

An ADIZ is a logical end point to the past two years of Chinese activity. It effectively gives China control of aircraft movements through the region. One way to weaken China’s case for ADIZ would be for neighbouring countries to agree to share data on all aircraft movements.

Finally, Australia needs to bite the bullet and start to exercise an international right to freedom of navigation through the region. This is often asserted as a critical Australian interest. We should make use of this legally accepted right or otherwise face the prospect of losing the capacity to safely transit the region.

The South China Sea dispute is rapidly morphing into a fully fledged crisis, driven by Beijing’s haste to consolidate its gains while Barack Obama remains in the Oval Office, by a belated American realisation that the “rocks and shoals” really do have strategic significance and by a growing sense of panic in the region that China is not going to stop.

Into this mix we now have an Australian defence policy that rightly designates maritime Southeast Asia as the critical locus for our own national security. Now the strategy must be implemented. We do indeed live in exciting times, as the Prime Minister never fails to remind us.

Peter Jennings is executive director of the Australian Strategic Policy Institute. He led an external experts panel advising the government on the new defence white paper.

Weekend Australian, p18