If China isn’t already Asia’s pre-eminent superpower, it will be by 2030 if US President Donald Trump keeps up his unpopular foreign policy decisions, according to an Australian think tank.

The Lowy Institute unveiled its inaugural Asia Power Index on Tuesday in New York, painting a compelling picture of the current and future power balance in a region that houses three of the world’s four largest economies and an increasing majority of the global population, trade and production.

It found that, although not geographically an Asian nation, the United States remains the most powerful of 25 countries, giving it a score of 85. It topped five of the eight sub-measures – economic resources, military capabilities, resilience, defence networks and cultural influence. China, meanwhile, ranked second with a score of 75.5 and led the remaining sub-measures – future trends, diplomatic influence and economic relationships.

Japan, India and Russia rounded out the top five most powerful Asian nations, while Nepal, Laos, Mongolia and Cambodia sat at the bottom end of the ranking.

Lowy listed America’s unrivalled military force and its defence networks, its university education system and its widely consumed media as its key influences in Asia – after all, China Daily is not as widely read for US news as The New York Times is for China news.

But even with its fire power and far-reaching cultural influence, America’s days at the top in Asia look numbered with its current commander-in-chief.

Lagging well behind China in terms of economic relationships, the institute called Washington’s diplomatic stance in the region “a glaring weakness” – one that is being continually damaged by nervousness about the Trump administration and its foreign policy decisions.

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“Whether it is China or the US as the primary power in Asia, both face challenges in Asia,” said Herve Lemahieu, research fellow and director of the Asia Power Index Project at the Lowy Institute.

“For the US, the Achilles’ heel is really economic relationships – we can see that very clearly.

“The Trump presidency is undermining the very aspects of US power that give it that predominant competitive edge over China. He is a sceptic of the alliance system, he is against free trade, and any form of trade war between China and the US would obviously involve other countries as well.”

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While the US seems to be falling on its military might across Asia to sustain its eroding position in the region, China’s softer “Belt and Road Initiative” is doing the opposite – albeit still marred by distrust and scepticism from its own neighbours, Lemahieu said.

“Beijing has surpassed Washington as the most influential capital in the Asia-Pacific region. And that is down to the fact that it understands its economic relationships, and it understands its strategic agenda which it can drive through initiatives like the belt and road,” he told This Week in Asia ahead of Tuesday’s launch.

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By 2030, the institute predicts China’s GDP to be almost twice the size as the United States in terms of purchasing power and it will hold top position as Asia’s most powerful nation. But such an accolade will not come easy. The country has an ageing population, which is expected to decline by 42 million working-age people by 2030.

Add to that China’s active boundary and territorial disputes with India, Japan, Vietnam and other nations concerned with the South China Sea, its dependence on energy imports and what Lowy describes as its “underdeveloped defence network”, which makes it vulnerable to a military and strategic counterweight.

“[China] is confronted by a political geography that isn’t entirely in its favour. It is surrounded by countries with whom it has a number of territorial and boundary disputes, and Vietnam and India will remain deeply sceptical of China intentions,” Lemahieu said.

“It is also up to Beijing to create confidence in the fact that it is a benign power – and that is far from clear. That sort of confidence in the US is still intact, despite the rise of Trump presidency.”

Lemahieu said until Beijing makes substantial reparations on the territorial disputes and matches US military capability, it will remain a contested force in Asia despite its economic influence.

And the race to assert military dominance across Asia is certainly not a one-horse race.

Lowy’s military capability measure offered an interesting reminder of the intensifying security situation facing Asia. While the US and China take first and second spots, Russia, India and North Korea follow as the next most powerful – beating even devoted US allies such as Japan, Australia and Singapore.

“Military strength remains vital in deterring potential military aggression, such as North Korea’s threats in Asia and beyond,” said William Courtney, adjunct senior fellow and executive director at US policy think tank RAND Corporation.

“If America were not to provide a nuclear umbrella to democracies in Northeast Asia, the risks of North Korean nuclear intimidation and coercion in the region would rise.”