The trend isn't good. Compared with the US, China's influence over south-east Asia is growing. Japan, meanwhile, has a lot of weight in the region but so far isn't using it much.

And Australia, as ever, should be doing more, because south-east Asian resilience is deeply in our interest - far more than it is for the US, for example.

One modest but helpful move we could make would be to assist our neighbours more with coast guard work, especially since their unwelcome maritime intruders will often be Chinese.

Researchers at the Lowy Institute, a think tank in Sydney, have a way of measuring international influence, boiling it down to numbers. They count things such as trade and investment data, diplomatic meetings and military contacts, then merge the figures to produce index values of influence, the ability to sway another country's policies.

In 2018, China was already ahead of the US in south-east Asia, with a balance of influence of 52 points to 48. (The index is arranged so the total is always 100.) In the latest measurement, for 2022, the balance has shifted to 54 to 46.

Economic clout is one of China's advantages anywhere; in south-east Asia there's the added strength of being so close. So China is vastly ahead of the US in economic connections with our near neighbours, by 70 points to 30. But China also puts more diplomatic effort into the region, and it even has a slight lead in cultural influence. Only in military connections is the US ahead.

"The United States is not competing effectively for influence in south-east Asia," says Lowy researcher Susannah Patton. "It is losing ground, which is primarily driven by the economic trend but also by a lack of high-level US focus with the region."

Pity the Americans, though. Other countries expect them to look after so many of the world's problems. Joe Biden can't be everywhere, nor can the US armed forces.

If China gains enough influence to steer policy decisions in south-east Asia, it can gain trade advantages. But a far bigger problem is that, if China has enough influence over our neighbours, they will help it militarily.

If it seizes Taiwan, defeating or deterring US intervention, we can forget any hopes of south-east Asian countries resisting Beijing. They just wouldn't see an alternative to obedience.

More than anything, we hope Indonesia will never go under China's thumb. With about 280 million people, it should have the strength to stand up for itself. Also, it's right next to us.

But the balance of Chinese to US influence in Indonesia shifted from 55:45 in 2018 to 60:40 last year, the Lowy Institute reports. China's economic relationship with Indonesia is four times as strong as the US's.

The US has two south-east Asian allies - Thailand and the Philippines. In both cases, the balance of influence over them has moved in China's direction. China's trade and investment connections with the Philippines have rocketed. Thais, meanwhile, aren't doing as many internet searches related to the US, revealing declining American cultural influence.

If south-east Asian countries are to resist pressure to do as China says, they must be convinced that someone is backing them up, countering a worryingly realistic message from Beijing's diplomats that the US is only a visitor to this side of the world, whereas China will always be here.

That's evidently a special focus of the Quad, an international partnership aimed at "supporting an open, stable and prosperous Indo-Pacific that is inclusive and resilient" (translation: "resisting China"). As south-east Asian countries must have noticed, three Quad members - Australia, India and Japan - flank them, while the fourth, the US, has powerful forces nearby.

In its description of the Quad, the Australian Department of Foreign Affairs and Trade manages to mention the Association of south-east Asian Nations five times in four paragraphs, even though ASEAN's members aren't actually in the Quad. We're trying to tell them that they have support.

Japan could be more influential in south-east Asia if it wanted to be. As another nearby economic giant, it has plenty of trade and investment connections. Japan's culture is also far more interesting to south-east Asia than most Australians would imagine: fashions, television shows, anime. More generally, it's a highly admired country (in China, too, by the way).

Japan has only just begun to throw its weight around - ever so politely, of course. A welcome move is holding a joint exercise this week in which the Japanese, US and Philippine coast guards are working together in Philippine waters.

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This is in fact one aspect of international cooperation that we could be doing a lot more of.

The US agreed last month to similarly assist Papua New Guinea, a move that raised the question of why Australia wasn't already giving PNG all the help it needed.

Similarly, we can ask why Australia isn't up there helping the Philippines. Why do we always expect the Americans to do the work?

We've given little patrol drones to Manila, presumably at modest cost, but it would be far better to have ships with Australian flags and crews turning up in Philippine ports, with the locals knowing that we're there to assist.

Our coast guard, the Border Maritime Command, sometimes exercises with Indonesia's. Now how about offering to do the same with more south-east Asian countries?

Anything to counter China's influence would be helpful.