_When somebody is reaching the end of their life, they often suffer from lots of apparently unrelated ailments fevers,_chest pains, unlucky falls. Something similar may happen when a strategic order is dying.

Across east Asia, the past month has seen a rash of diplomatic and security incidents that are symptoms of a wider sickness.In late July, the Chinese and Russian air forces staged their first ever joint aerial patrol in the region, causing South Korean warplanes to fire hundreds of warning shots at Russian intruders. The South Koreansare also facing the most serious deterioration in their relations with Japan in decades with the Japanese imposing trade restrictions last week in a dispute that has its origins in the second world war. North Korea has also just restarted missile tests, endangering US-led peace efforts.

All of the other east Asian flashpoints Taiwan, the South China Sea, Hong Kong and the US-China trade war are also looking more combustible. Protests and strikes in Hong Kong are still gathering momentum.

Chinese officials are now openly discussing military intervention and last week a White House official drew attention to a massing of Chinese troops, just across the border from Hong Kong. For the Trump administration, however, the major preoccupation remainsits trade dispute with China, which also intensified last week, with the US imposing a new set of tariffs.

July also saw a Chinese oil exploration vessel enter waters claimed by Vietnam, leading to a stand-off between heavily armed Chinese and Vietnamese ships. The government of the Philippines, too, sounded the alarm about Chinese naval incursions and called for American assistance. Chinas growing assertiveness was underlined by the news that Beijing is developing a military base in Cambodia, its first in south-east Asia.

Tensions over Taiwan continue to rise. In late-July a US warship sailed through the Taiwan Strait and China released a defence white paper, accusing the Taiwanese government of pursuing independence and threatening a military response. The US meanwhile is talking of soondeploying intermediate-range missiles in east Asia, following its pullout from the Intermediate-Range Nuclear Forces Treaty last week.

On the surface, many of these incidents seem unconnected. But collectively they point to a regional security order that is coming apart. Americas military pre-eminence and diplomatic predictability can no longer be taken for granted. And China is no longer willing to accept a secondary role in east Asias security system. In these new circumstances, other countries including Russia, Japan and North Korea are testing the rules.

The past 40 years have been a period of unprecedented growth and prosperity across east Asia, which has also transformed the global economy. But Asias economic miracle relied on peace and stability. Those conditions were established in the mid-1970s, with the end of the Vietnam war and Americas rapprochement with China.

Since then, America has tolerated and even facilitated the rise of China. In return, China has tacitly accepted that America would remain the dominant military power in the Asia-Pacific region. You could label these arrangements the Kissinger order in east Asia, after Henry Kissinger, the US secretary of state who helped broker the new relationship between America and China in the early 1970s.

But both President Xi Jinping of China and President Donald Trump of the US have rejected basic elements of the Kissinger order. Mr Trump has abandoned the idea that US-Chinese ties are mutually beneficial, by launching his trade war, while Mr Xi has set about challenging Americas strategic pre-eminence.

There will come a point when America and Australia will part company on policy towards China.

Senior Australian diplomat

Chinas challenge to American power has raised the question of how long the USs strategic dominance in Asia will last. Rather than offering reassurance, Mr Trump has added to the uncertainty by openly questioning the value of US alliances with Japan and South Korea. As one Asian foreign minister put it recently: The damage that Trump has done will outlive Trump.

The loss of the USs regional authority is evident in Washingtons inability to control the feud between Japan and South Korea, its two most important regional allies. Even the Australians are beginning to doubt American leadership, with one senior Australian diplomat telling me recently that, with the trade war intensifying, there will come a point when America and Australia will part company on policy towards China.

But doubts about American leadership are not matched by any desire to embrace a China-dominated region. On the contrary, from Tokyo to Taipei and from Canberra to Hanoi, there is growing anxiety about Beijings behaviour. That anxiety is only increased by the growing closeness between China and Russia.

From Moscows point of view, the recent joint air patrol underlined Russias return as a Pacific power just as military intervention in Syria signalled its re-emergence as a power in the Middle East.

The Kissinger order in east Asia did not resolve most of the historic disputes and rivalries in the region. But it helped to freeze regional conflicts in place, buying time for peaceful development. Now the geopolitical climate has changed so frozen conflicts are moving again. As the ice melts, things can move fast in dangerous and unpredictable ways.gideon.rachman@ft.com

**Gideon Rachman**is chief foreign affairs columnist for the Financial Times. His particular interests include American foreign policy, the European Union and globalisation.