The ballast keeping the relationship between the world's two largest economies upright lies in their cooperation on global public good, which is being undermined by the Trump administration's "America First" doctrine, a senior researcher with a leading US think tank said.

Without that ballast of cooperation, it is likely that US-China relations will become more volatile and bounce from good to bad and back on the basis of small events, said David Dollar, senior fellow with John L. Thornton China Center of the Brookings Institution.

For years, academics and politicians in both Beijing and Washington have agreed that trade relations are the foundation of bilateral ties, given that China and the United States are each other's largest trading partners.

But Dollar said that China's economy is much less export-dependent today than it was before the global financial crisis in 2008.

"It is becoming less true that the economic relationship is the foundation of the overall relationship," Dollar, who specializes in foreign policy and global economy and development, said in an interview.

"I see the 'ballast' in the relationship being the cooperation on global public good," he said on Monday.

The two most important areas of public good for the US and China to cooperate on are climate change and free trade, the former World Bank and US Treasury China representative said.

However, US President Donald Trump's "America first" doctrine puts little or no value on these, he said.

"We are in danger of losing that ballast now because the Trump administration has a negative view of many global public goods," Dollar said.

The US-China cooperation on climate change, culminating in the Paris Agreement in 2015, has been one of the best examples of the two countries working together to provide global public good, Dollar said.

Other examples include their cooperation on nuclear nonproliferation in the case of Iran, on Ebola virus control in Africa and on piracy off the coast of Africa, Dollar said.

The Belt and Road Initiative, proposed by Chinese President Xi Jinping in 2013, has become the most popular public good China is providing to the world, Foreign Minister Wang Yi said in March.

Dollar said the Belt and Road Initiative could provide public good in the form of greater integration and faster development of poor countries.

huanxinzhao@chinadailyusa.com