Power politics is back in the Indo-Pacific. For all the talk about rules and a free and open region, it’s the deteriorating strategic order Australia and its like-minded friends should be really worrying about – and taking more action to influence before it’s too late.

This is the grim takeaway from the region’s top security forum, the Shangri-La Dialogue, held in Singapore last weekend amid intensifying rivalry between the United States and China.

On show were key dynamics of the Indo-Pacific’s great power competition: A chilling articulation of China’s revisionist aims. A reaffirmation of US security commitments that didn’t quite hit the mark. Upbeat cameos from Australia and other middle powers about their investments in Indo-Pacific resilience. And palpable anxiety from everyone about the geopolitical costs of a US-China trade war that’s unpicking the interdependence at the heart of the region’s liberal peace.

It was a sobering gathering that blended the Thucydidean logic of US-China tensions with the reality of the Indo-Pacific’s collective action problem.

Chinese Defence Minister General Wei Fenghe embodied the challenge bearing on the region. Blaming Washington for contemporary tensions, he delivered an unapologetic statement of Beijing’s preparedness to do whatever it takes to secure “core interests” like Taiwan over which “China will fight at all costs”.

The general also white-washed his country’s use of force and coercion. Arguing “China shall never threaten anyone” or “establish spheres of influence,” he discredited well-founded concerns that China’s expanding military presence, political interference and economic statecraft is calibrated for just that.

Wei’s bottom line? Accommodating China’s interests and security concerns is the quid pro quo for keeping the peace.

This isn’t a hollow threat. China’s navy – already Asia’s largest – is rapidly growing and modernising. It now offers Beijing the capacity to tail every foreign warship in the South China Sea simultaneously, with plenty of grey-hulls left over for making its presence felt further afield as Sydneysiders discovered this week when Chinese warships steamed into the harbour.

Coupled with China’s increasingly sophisticated air force, intelligence capabilities, and proliferation of missiles on its coastline and artificial islands, Beijing has the ability to impose devastating costs on anyone that approaches its near abroad. This looks like a sphere of influence to most defence planners.

America isn’t rolling over. As acting US Defense Secretary Patrick Shanahan made clear, the Pentagon sees the Indo-Pacific as its “priority theatre” and China its top competitor. And it’s working to bolster military deployments across the region.

While Shanahan held out the potential for a “cooperative relationship” with Beijing, he was unequivocal about the aim of US strategy, declaring: “behaviour that erodes other nations’ sovereignty and sows distrust of China’s intentions must end”.

But he was also unequivocal about difficulty of this task.

In surprisingly stark terms, Shanahan acknowledged the US can’t succeed in its strategy alone. “We are investing in you, and with you,” he reassured, but “We need you to invest further in yourselves…to take more control over your sovereignty and your own ability to exercise sovereign choices.”

Herein lies the collective action dilemma that’s complicating Indo-Pacific strategy – the US, Australian and Japanese-led effort to construct a collective balance of power to deter Chinese adventurism, and to ensure regional countries are sufficiently resilient to blunt economic and political coercion.

This strategy requires active steps by south-east Asian and Pacific nations on issues like: strengthening defence capabilities; granting the US military access to strategic locations; and safeguarding the integrity of critical infrastructure.

But many aren’t willing to make these choices. They’re afraid of sacrificing prosperity and incurring Beijing’s wrath at a time when Donald Trump’s unilateral assault on the rules-based order makes them question America’s capacity and willingness to deliver on its strategy. Many are instead urging detente.

Singaporean Prime Minister Lee Hsien Loong captured the sentiment: “China is growing and its growth has to be accommodated; other countries have to adjust and China has to adjust.” Put differently: “The US and China need to work together.” Prime Minister Scott Morrison concurs, saying of Lee’s speech “there are many insights that Australia would share”.

Such comments frustrated Americans at Shangri-La. They regard China as an existential threat and believe sniping at US policy – which is trying to make the best of strategically tone-deaf president – is a self-defeating approach for a region that doesn’t want to be dominated by Beijing.

On this they’re right, but it somewhat misses point.

Regional countries are motivated by fear and need. It’s not that they don’t fear China’s rise or are blind to the risks that flow from China’s satiation of their economic needs. It’s that they also fear the consequences of what they perceive to be erratic American policy – on trade, technology and multilateral governance – and are desperately in need of credible reassurance.

If Indo-Pacific strategic order is to be upheld, this perception gap between America and its regional partners must be closed.

Australia can help. As a US ally that shares regional concerns about US-China tensions but is also making hard choices to shore-up our corner of the Indo-Pacific – boosting defence spending, providing infrastructure, protecting 5G networks etc – Canberra is uniquely placed to broker mutual empathy.

But it will take deft diplomacy and considerable resources to spur the kind of collective action that’s needed to ensure stability on our terms.