Admiral Harry Harris, Commander of US Pacific Command, is known for making a splash in international forums. Last year he introduced the term 'Great Wall of Sand' in a speech in Canberra warning of China's manufacture of militarised islands in the South China Sea.

Now, in his wide-ranging speech at a grand multilateral forum convened in New Delhi, Admiral Harris has dropped the 'q' word that some deem too sensitive for polite diplomacy.


Ships of the US and Indian navies work together during Exercise Malabar 2014. (Wikipedia.)

He has called for India, Japan and Australia to consider the idea of a quadrilateral dialogue with the US, to caucus on security challenges to the rules-based regional order. The obvious context for this is China and its destabilising behaviour in extending self-proclaimed authority over much of the contested South China Sea.

Beijing will not be pleased. It will likely reject this fresh talk of the quadrilateral as a provocation, an Asian NATO, a club for containment, a gang of four determined to strangle its rise – even though what is being proposed is just a dialogue, not a formal naval coalition, as some media headlines imply.

Actually, if China does protest, it will affirm precisely why the quad idea is worth keeping alive. There is something deeply unpersuasive about a rising power, whose strategic actions have stirred the anxieties of so many other countries, insisting that others have no right to confer or think about security in numbers.

The speech to India's new Raisina Dialogue on 2 March is not the first time Admiral Harris has voiced the forbidden quad word. It builds on recent Congressional testimony in which he revealed Pacific Command's ambition to build a partnership of the four Indo-Pacific democracies.

Nor is the quad exactly new. A previous four-country initiative emerged briefly in 2007, building on the cooperation of the four maritime friends in rapidly providing humanitarian assistance after the Indian Ocean tsunami of December 2004.

This led to precisely one brief meeting of a handful of officials on the sidelines of the ASEAN Regional Forum forum in 2007, where the agenda was disaster relief. Chinese demarches followed. A few months later the four nations, plus Singapore, held a large naval exercise in the Indian Ocean, and China's complaints reached a crescendo.

A change of government in Australia, with Labor getting cold feet, a change of prime minister in Japan and no sustained enthusiasm in Tokyo or Delhi meant that China's pressure won out. The original quad went quiescent in early 2008.

In retrospect, the quad was ahead of its time. Back then, concerns about how China would use its growing power were the preserve of intelligence analysts, military planners or the occasional far-seeing politician. Assertiveness and coercion had not been made manifest in the South and East China seas. Chinese submarines were strangers to the Indian Ocean. China's charm offensive in Southeast Asia was in full swing. Beijing showed little sign of the over-confident nationalism that surfaced when financial crisis shook the West.

The main criticism of the quad back then was that it would needlessly provoke China down a perilous path of military modernisation and destabilising behaviour driven by insecurity or justified by perceptions of encirclement. Yet even while the quad foundered, Beijing chose to follow such a road anyway. The tantalising question is whether China would have been less assertive in challenging the regional order had new forms of cooperation among other powers been allowed to take root.

Of course, the quad alone is not the solution to the region's security ills. China has legitimate interests as a major power in the Indo-Pacific region, including as a great trading nation dependent on imported oil and with increasingly far-flung responsibilities around its investments and diaspora. Like India, Japan, and others, China can and should contribute to safeguarding the maritime commons, and its efforts against piracy in the Gulf of Aden have been welcome. So of course other powers should engage China as a dialogue partner, even while they build a context of balancing.

The lingering phantom of the quadrilateral has served the worthwhile purpose of making the world safe for other creative kinds of security geometry. These have dilute Chinese power in a vast Indo-Pacific region where other powers have rights and interests too. Beijing has reluctantly learned to tolerate trilateralism, the various thriving three-way security dialogues that have emerged: Australia-Japan-US, India-Japan-US and most recently Australia-Japan-India.

The US and its Indo-Pacific allies and partners are profoundly troubled by China's actions in the South China Sea and by their own lack of good options to turn the tide without raising risks of confrontation and conflict. So it makes sense for them to explore oblique ways of pushing back and signalling solidarity in favour of a rules-based order. A quadrilateral dialogue would allow them to exchange confidential assessments and develop shared approaches to shaping and limiting Chinese assertiveness, in the interests of small and medium countries and regional stability. A quad could also allow the four democracies to remain in step in other ways, such as counselling each other against rash steps or miscalculations.

Ironically, the four-nation strategic diamond may remain most effective as an idea rather than a policy. So it is reasonable for Admiral Harris to refloat it.

But let's hope there are also efforts underway to take soundings of political comfort levels in New Delhi, Tokyo and Canberra. Tokyo is already openly on board, including through Prime Minister Abe's rhetoric of a security 'diamond'. In New Delhi and Canberra, it is fair to assume that minds are not closed, but solidarity will more likely grow through quiet consultation than public zeal.

In any case, the region already benefits from a robust web of trilaterals, plus a remarkable thickening of bilateral strategic links among all four nations, for instance naval exercises between India and Australia, coordination between India and Japan in strengthening the maritime capabilities of Southeast Asian nations, plus logistical, training and technology cooperation between Japan and Australia.

One of the drivers of this trend has been convergent worries about Chinese power and the way it is being used in the South China Sea. In this way, the maritime democracies already have the building blocks of a quadrilateral by accident if not design.