After Barack Obama's Air Force One touches down in Brisbane on Saturday, and the American president fulfils the day's G20 obligations including the prime ministerial barbecue, Obama will make his way to Queensland University and deliver the sequel to the  heralded "pivot" speech  that he famously made to a joint sitting of the Australian Parliament House.

Much has changed since the world's most powerful man last came to Australia, in December 2011, to reveal his "rebalancing" of military and diplomatic heft to the Asia-Pacific. The underlying strategic logic, however, has not. In the eyes of senior Australian, American and Japanese officials, in the space of three years China has shifted gears from occasionally testing boundaries, norms and institutions when they do not suit to relentlessly challenging the regional rules-based order.

Since Obama's last visit, the People's Liberation Army unveiled new weapons systems designed to challenge the US Navy in "blue waters" far from home; incursions into Japanese-administered waters became a daily norm and deep anti-western solidarity was forged with Vladimir Putin's Russia. The vessels from the Russian Pacific Fleet that have followed Putin to waters off Queensland, for example, are the same ones that joined the PLA Navy for unprecedented drills in May this year. And the "freedom of navigation" rules those visiting Russian ships are working within - painstakingly established by the Americans and Soviets to avoid catastrophic miscalculations in air and sky during the Cold War - are the same ones that Chinese  Air Force fighters challenged during those joint Russian drills with two Top Gun-style close intercepts of Japanese surveillance planes ("with afterburners blazing," says a senior Japanese official).

The Chinese party-state has been forcefully pushing back not only against the military and economic reach of Western power but also the "so-called universal values" that underpin it. Coercion abroad has been matched by oppression at home in a sustained police and propaganda blitz against liberal-minded lawyers, journalists and online commentators who have endeavoured to make the world's most powerful political party and bureaucracy externally accountable. All of these shifts in Chinese intensity and ambition, if not direction, have coincided with the ascendancy of an extraordinarily potent leader, Xi Jinping, who was also due to fly into Brisbane overnight.

Xi, the world's second most powerful man, arrives in Australia fresh from hosting a successful APEC meeting and introducing a new stage in China's development. In the space of a few weeks he outlined a series of alternative Chinese-anchored economic institutions, forged a kind of truce with Japan's Shinzo Abe and proved he could be willing and able to work with Obama to combat global problems, most conspicuously with climate change. "China has now assumed Great Power status," said a headline on the website of The Atlantic magazine on Friday, amplifying an argument that followed about how China had graduated from being a large, powerful and clumsy "overgrown teenager".

On Monday, after Obama has fleshed out his vision of a shared, peaceful, prosperous, rules-based, American-anchored Asia-Pacific order, Xi will get his turn to flesh out his own parallel vision to a joint sitting of Parliament House. Xi's message will be one of reassurance uncannily similar to Obama's, if the new motto of an "Asia Pacific Dream" and the tone of recent weeks is anything to go by.

"What is the Asia-Pacific Dream? It's a lot like Obama's dream," says Jia Qingguo, Dean of Peking University's prestigious department of International Relations. "There will be a lot of overlap between the two speeches," he says. "Both countries want peace, stability and prosperity of the region because it is in their common interests," he says. "I think Xi will stress co-operation instead of confrontation."

Professor Jia, who is also a standing committee member of one of China's two quasi-parliamentary assemblies, which gives him opportunities to meet with senior leaders, makes a crucial point which may not be widely understood: the fact that both Xi and Obama have chosen Australia to make their landmark statements about the regional order is no coincidence. Australia is shaping as a pivotal player in the US-China rivalry – perhaps even the pivotal player - because no other nation except South Korea has anything like its degree of economic enmeshment with China and military dependence on the United States.

Without prompting, Jia adds: "In realising their proposed visions of course, neither party will push Australia to join with them at the expense of the other, unlike what Australians are imagining."

It has become a truism that Australia's central foreign policy challenge in the foreseeable decades of this century will be how it manages the spectrum of benefits, expectations and traps that lie between American and China. In contrast with Jia's reassurances, and the collaborative line that Xi is likely to adopt on Monday, a very different message has been conveyed through webs of official and non-official channels. Only a handful of bombastic PLA commentators and international relations specialists have made the "strategic choice" argument publicly, however, making it difficult to assess the extent to which it represents an official line.

Xi's "Asia-Pacific Dream" motto is an extension of the "China Dream" that he brought with him upon assuming the top positions in the party and the military on this day exactly two years ago. The China Dream has never been defined beyond a vague aspiration of prosperity, happiness and national and military power. One reference point, which would have been near the front of Xi's mind, was a new book of the same name by a PLA senior colonel, Liu Mingfu, which reduced the world to a two-nation track race between the United States and China. Liu met with me at the time because he wanted to convey a message about the "American-orchestrated" territorial conflict with "militarist" Japan that had just erupted over sovereignty of the Japanese-administered Senkaku/Diaoyu islands in the East China Sea.

"American hegemony is not at its dawn and not at its zenith, it is at its sunset and night is coming," said Snr Col Liu. He switched to an animal metaphor to make room for a point about Australia.  "America is the global tiger and Japan is Asia's wolf and both are now madly biting China," he said. His message: Australia would desist from "dancing-with the wolf', with the assistance of Chinese beneficence, and revert to form as a "kind-hearted lamb".

Professor Hugh White, the former deputy secretary of the department of defence, now at the Australian National University, has framed the economic and strategic dilemma in its starkest form: "the China choice". The Abbott Government, it seems, has gone out of its way to test the thesis, with a series of moves to tighten ties with both Japan and the United States while publicly criticising Chinese excesses.

The most revealing example came three weeks ago, when Australia (and South Korea) opted out of a group of Asian nations agreeing to join China in collectively negotiating the terms of a China-led Asia Infrastructure Investment Bank (AIIB). The decision was roundly condemned by commentators as a reflexive show of support for the US and a slap in the face to China. The reaction, say officials and some retired officials, presents the ultimate case study of  how Australia's strategic flexibility has been ignored.

"The AIIB displays in its most clear form that Australia has a very critical role as a swing state," says Ely Ratner, Deputy Director of the Asia-Pacific Security Program at the Center for a New American Security. "In the case of AIIB, it is the critical vote."

Ratner, who worked on the China Desk at the US State Department under Hillary Clinton, says Australia did not blindly side with an oppositional America but chose to maximise its bargaining power to encourage China to return with standards of control, governance and transparency which were in line Australian standards. "I don't agree with the Hugh White which is 'throw your arms in the air and agree with whatever Beijing wants to do'.  He concedes, however, that the AIIB episode was also a learning episode for Washington, which lobbied in backrooms rather than standing on the principles of public transparency which it espoused. "We may have been right on policies but the optics were terrible," he says.

Confirming Ratner's thesis, Chinese leaders have since conveyed to Australian officials that the door to joining the Asia bank is still wide open and they will seek to satisfy Australia's governance requirements. On Monday, Prime Minister Tony Abbott looks likely to defy an endless stream of dire predictions by sticking to its strategic guns while signing a free trade agreement with Xi.

And this, broadly, is a pattern that is being repeated across the region as nations succeed in maximising economic engagement with China while going their own ways on the harder-edged questions of territorial sovereignty.

The stronger China grows, and the harder it has pushed under Xi, the more its neighbours have sought coalitions of assistance from each other and refuge under the American security umbrella. Even with shrinking space for free expression there are Chinese scholars who have found ways to communicate that coercion can be counter-productive.

In contrast to the prevailing streams of Australian commentary, there are few credible voices in China that predict that the growth of Chinese power is so inexorable, and the choices of lesser nations so constrained, that the "swing states" like Australia have no choice but to be drawn inexorably into China's political orbit.  Outcomes  may well depend less on the vagaries of Australian political decisions than much bigger questions about the evolving nature of China.

There are many in China who have lost faith in the prospects of the legal, market and political reforms they believe to be necessary to support sustainable economic growth, reduce the insecurities of the Chinese political elite and enable the country to deal with nations as equals in a pluralistic world order. Optimists, however, can point to economic and legal reforms flagged but as yet unimplemented in recent party plenums.

Where will Australia choose to sit in 20 years time?

"It's very difficult to predict," says Jia, the international relations dean at Peking University. "It has a lot to do with how much success China has made in implementing the reforms outlined in third plenum and the fourth plenum of the 18^th party congress," he says. "The extent to which China can implement these reforms will probably have a very huge impact on what the Asia Pacific will look like. If China is successful, the future will be much brighter. If not, there will be much more conflict, I think."

On the evidence so far, the China choice is not for Australia to make alone, it seems, but also China.