The Australian decision to allow the rotation of American troops in Darwin has caused indignation in Beijing. The editorial of the state-run Global Times argued “There is real worry in Chinese society concerning Australia’s acceptance of an increased US military presence” and such an Australian “psychology will influence the long-term development of the Australia-China relationship”.

These are ominous words coming from our largest trading partner that also happens to the second largest economy in the world and the most formidable Asian military power. But it also reflects the reality that despite China’s economic importance and almost a decade of “smile diplomacy”, Asia’s largest power remains a surprisingly isolated and distrusted power.

Few countries in the region want to needlessly poke China in the eye and will refrain from commenting about the decision to allow American troops into Darwin. But they will be silently nodding in agreement from the sidelines. Every major country in Asia — Japan, South Korea, the Philippines, Vietnam, Singapore, Indonesia and India — has called for a renewed American commitment in the region and reinforced or improved strategic relations with Washington over the past two years. This does not mean basing American troops on their soil in every instance but it does mean an enhanced American presence in the Indo-Pacific. In other words, Australia is not alone on this issue.

The open secret throughout the region is that this is all about China. Why the concern about China’s rise? Here are three reasons.

First, China’s military spending has increased at levels faster than its already spectacular GDP growth for the past 20 years. This has occurred regardless of whether its relationship with American and other powers are improving or deteriorating. This has occurred during a period of uninterrupted peace for about 35 years in the region. In other words, the rapid rise in China’s military spending appears to take place regardless of its external environment and level of imminent threat in the region.

Second, it is becoming more difficult to accept China’s military modernisation as solely designed to prevent Taiwanese independence as is still the official line. While it is legitimate for any rising power to build capabilities to protect its interests, the lack of transparency as to what the People’s Liberation Army is up to, and why, will naturally create concern.

Third, as China grows richer, it is becoming more rather than less assertive. Note the intensification of its claims over four-fifths of the South China Sea or the basing of 250,000 troops just north of the Indian-held territory of Arunachal Pradesh, which China claims. History tells us that this should have been expected. But governments vainly hoping that China could be different have been forced to respond. The rise of continental giants tends to trigger a coalition among maritime powers over time.  And the only effective check on Chinese might is American power.

Finally, what will this mean for the economic relationship with China? The likelihood is that it will have no impact. China buys our iron-ore because it has to, not because it wants to. And that will not change in the foreseeable future. Indeed, Chinese trade with all major economies is the region such as Japan, South Korea, Vietnam, and India has increased despite political tensions deepening with all these countries. The evidence is that China’s capacity to economically punish neighbours is weak.

China’s rise in Asia has made the region a much more complicated place — that is just a fact of life. In such a complex environment, most countries would rather have the Americans in rather than out.

*Dr John Lee is the Michael Hintze Fellow for energy security and adjunct A/professor at the Centre for International Security Studies, Sydney University, and a non-resident scholar at the Hudson Institute in Washington DC