With the revelation last week that China had reportedly deployed surface to air missiles on Woody Island, rising tensions in the South China Sea have once again been thrust into the global spotlight.

As readers of The Interpreter are likely aware, Labor has been forthright about our position on what is occurring in the South China Sea.

We believe that Australia and other like-minded countries should act to support the international rules-based order in the South China Sea. This is because we recognise that Australia has benefited enormously from the international system and we believe its maintenance is essential to our economic and national security interests.

The international system provides a platform from which we can project our voice and national interests well beyond the comparative size of our economy or armed forces. The current system is not perfect, but it is the best check we have against ‘might is right’.

That’s why I believe the Government should consider authorising a freedom of navigation operation — a FONOP — in the South China Sea as a demonstration of Australia’s commitment to upholding the rules-based international order.

While Labor has been clear in its views, the Turnbull Government’s position has been marked by ambiguity. The Government repeats often that it supports freedom of navigation and overflight. These are appropriate public statements. Less appropriate has been its use of carefully constructed language to imply that Australia has been taking action in the South China Sea.

Ask the Turnbull Government about its policy on the South China Sea and you will be met with some variation of this:

Australian vessels and aircraft will continue to exercise rights under international law to freedom of navigation and freedom of overflight, including in the South China Sea.

This carefully constructed language implies that the ADF is engaged in activities in the South China Sea of a similar nature to the FONOPs conducted by the US.

But when asked directly in Senate Estimates if the ADF conducts deliberate freedom of navigation and overflight activities as part of Operation GATEWAY, Air Chief Marshal Binskin replied 'no'. Asked if ADF naval vessels transiting through the South China Sea conduct FONOPs, Air Chief Marshal Binskin said: 'if your definition of the freedom of navigation is inside territorial waters, the answer is no'.

On this important issue, the Turnbull Government is resorting to ambiguous word games.

This is very different to the clear position Foreign Affairs Minister Julie Bishop enunciated following China’s unilateral imposition of an Air Defence Identification Zone (ADIZ) in the East China Sea in 2013. When asked about her strong stance on the ADIZ, and the stern rebuff she received from China, Ms Bishop said: 'China doesn’t respect weakness'. Ms Bishop also said that 'when something affects our national interest then we should make it very clear about where we stand and not be ambiguous'.

Yet ambiguity is precisely what defines the Turnbull Government’s approach to the South China Sea.

This shift in approach appears to have coincided with the change in prime minister last year.

For all his faults, Tony Abbott was generally clear in his views on national security matters; people knew where he stood, even if they didn’t agree with what he had to say. Malcolm Turnbull, in contrast, likes to deliver Delphic sermons replete with metaphors drawn from the Peloponnesian War.

Mr Abbott and Mr Turnbull do not just differ in their oratory style; they also differ fundamentally in their view of the world. Few would argue that Mr Abbott is anything but thoroughly orthodox when it comes to geopolitics. Mr Turnbull could not be more different. Nowhere is this clearer than in two speeches Mr Turnbull delivered in 2011 — to the London School of Economics and to AsiaLink — and in his 2012 review of Hugh White’s book, The China Choice.

Across these works, Mr Turnbull displays a starkly different worldview from Mr Abbott. Mr Turnbull warns of the perils of Australian governments having a 'doe-eyed fascination with the leader of the free world'. He talks of Americans 'developing an inferiority complex', and of the 'risk that a combination of fear, envy and resentment will lead America into treating China as an enemy'.

Mr Turnbull has said that 'China has shown no interest in territorial expansion beyond, at some future date, reuniting Taiwan' and, on the South China Sea, that 'China is hardly alone in claiming islands and rocks far from its shores'. He also states that the 'best and most realistic strategic outcome for East Asia must be one in which the powers are in balance, with each side effectively able to deny the domination of the other'.

As Greg Sheridan argued at the time, a cynic might be inclined to think that Mr Turnbull espoused these views in an attempt to differentiate himself from Mr Abbott. In Mr Sheridan’s words: 'The cynical interpretation would be reassuring. I fear that Turnbull actually believes this nonsense'.

That Mr Turnbull is entitled to a different worldview to Mr Abbott — or indeed to the Labor Party — is not in question. But when the Government he leads will not explain key foreign policy positions, Mr Turnbull is negligent in his duty to the Australian people.

It is time for Mr Turnbull to explain just what his views are on this pressing security issue in our region.