China's a big problem not just because it's aggressive and unfriendly - plenty of countries are - but because it has a big population that's getting richer, giving it a lot of economic and military heft.
But that population is about to get smaller, maybe quickly. The smaller it gets, the less will be the challenge for other Asia-Pacific countries to resist China.
We're talking here about decades into the future, not the worrying strategic situation of the 2020s and 2030s, which will hardly be affected by changes in the Chinese population. But this issue is still worth thinking about, because China looks like a very long-term problem.
Its population, 1.412 billion last year, should top out by 2025, according to various experts. The fertility rate, the number of babies born per woman, fell below the replacement level of 2.1 in the early 1990s, but there's a kind of momentum in demography that causes a population to keep rising for a while after passing that threshold. That time lag is now expiring in China.
What's amazing is how quickly births are falling. Based on a census last year, China's fertility rate is down to 1.3, lower even than what is seen in Japan, which is famous for facing a declining population. (The rate is 1.66 in Australia, but we more than offset our shortage of babies by bringing in immigrants.)
China's lack of children has a lot less to do with the famous one-child policy than most people imagine, and not just because the government, waking up rather late to its ageing-population problem, has dropped most restrictions.
Relaxation of limits on births over the past decade seems to have made hardly any difference to them, showing that Chinese couples are increasingly satisfied with having just one child.
Quite often, they say they simply can't afford to have more. This has long been common in the cities, but it's spreading to the countryside, too.
Among my many friends in China, only one couple has two kids, and in that case money is no problem. The mother's parents are filthy rich.
After 2013, it was legal in urban areas for couples to have two children if one of the spouses had no siblings. I asked another friend whether he and his wife would take advantage of that, giving their little boy a sister or brother. He was almost speechless at the idea. (Admittedly, he's a world-champion cheapskate, and shockingly proud of it.)
The general limit became two children for any couple at the end of 2015, in which year the country had 16.6 million births. But the rule change led to just a small rise in production of babies, and it didn't last. In 2020 the country welcomed only 12 million - so there was a 28 per cent fall in only five years.
Now bits and pieces of statistics are appearing showing even more dramatic falls this year.
One populous province, Anhui in east-central China, is expecting 18 per cent fewer births in 2021 than last year. In the four years before then, the number of births had already dropped by 46 per cent, says the South China Morning Post, a Hong Kong newspaper. Anhui's provincial government describes birth numbers there as falling off a cliff.
There are similar figures for this year coming from maternity wards in Henan, which is another big province, and the city of Guiyang.
Demographic data usually doesn't usually shift that fast, so we need to regard the 2021 figures cautiously, says Bei Lu, a researcher at the University of NSW. For example, Chinese people move about a lot for jobs, making it hard for officials to work out immediately what's going on in any particular place, she points out.
Also, the pandemic may be having an effect. China's early-2020 lockdown seems to have disrupted baby-making for at least a couple of months.
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Still, there's no doubt that the population will fall; the question is how quickly. According to researchers at China's Xian Jiaotong University, if the fertility rate stays at 1.3, the population will halve by the mid-2060s.
Estimates from other researchers have been much less pessimistic, but they assume the fertility rate will be higher, which is looking increasingly improbable.
What if it falls to 1? Then the population will be down to about 700 million people as soon as 2050, the experts at Xian Jiaotong University say.
A China with fewer people will not be so hard to handle, though many countries in this region must be wondering whether they will be able to avoid becoming its subservient states in the meantime.
A lot of them are facing their own serious problems with population decline, and none more so than South Korea, where the fertility rate last year was estimated at only 0.84 births per woman.
Also, China's economy will keep growing even with fewer people, as it catches up to western development levels. Just how fast it can do that is another big question.
The population problem helps explain some Chinese government policies this year.
A ban on excessive working hours will make it easier for couples to contemplate raising children, and another on most out-of-school tutoring will reduce the cost of doing so.
New rules also seek to stop a trend in which popular culture, especially in the form of pretty-boy singers, has supposedly been turning young Chinese men into sissies. Officials seem to imagine that elaborate hairdos, jewellery and make-up could be a barrier to reproduction.
- Bradley Perrett was based in Beijing as a journalist from 2004 to 2020.