THE announcement by a Chinese military spokesman on November 23rd sounded bureaucratic: any aircraft flying through the newly designated Air Defence Identification Zone (ADIZ) in the East China Sea must notify Chinese authorities in advance and follow instructions from its air-traffic controllers. America’s response was rapid. On November 26th Barack Obama sent two B-52 bombers to fly through the new zone without notifying China (see article). This face-off marks the most worrying strategic escalation between the two countries since 1996, when China’s then president, Jiang Zemin, ordered a number of exclusion zones for missile tests in the Taiwan Strait, leading America to send two aircraft-carriers there.

Plenty of countries establish zones in which they require aircraft to identify themselves, but they tend not to be over other countries’ territory. The Chinese ADIZ overlaps with Japan’s own air-defence zone (see map). It also includes some specks of rock that Japan administers and calls the Senkaku islands (and which China claims and calls the Diaoyus), as well as a South Korean reef, known as Ieodo. The move is clearly designed to bolster China’s claims (see article). On November 28th Japan and South Korea sent aircraft into the zone.

Teenage testosterone

Growing economic power is bound to go hand-in-hand with growing regional assertiveness. That is fine, so long as the behaviour of the rising power remains within international norms. In this case, however, China’s does not; and America, which has guaranteed free navigation of the seas and skies of East Asia for 60 years, is right to make that clear.

How worrying China’s move is depends partly on the thinking behind it. It may be that, like a teenager on a growth spurt who doesn’t know his own strength, China has underestimated the impact of its actions. The claim that America’s bombers had skirted the edge of the ADIZ was gawkily embarrassing. But teenagers who do not realise the consequences of their actions often cause trouble: China has set up a casus belli with its neighbours and America for generations to come.

It would thus be much more worrying if the provocation was deliberate. The “Chinese dream” of Xi Jinping, the new president, is a mixture of economic reform and strident nationalism. The announcement of the ADIZ came shortly after a party plenum at which Mr Xi announced a string of commendably radical domestic reforms. The new zone will appeal to the nationalist camp, which wields huge power, particularly in the armed forces. It also helps defend Mr Xi against any suggestions that he is a westernising liberal.

If this is Mr Xi’s game, it is a dangerous one. East Asia has never before had a strong China and a strong Japan at the same time. China dominated the region from the mists of history until the 1850s, when the West’s arrival spurred Japan to modernise while China tried to resist the foreigners’ influence. China is eager to re-establish dominance over the region. Bitterness at the memory of the barbaric Japanese occupation in the second world war sharpens this desire. It is this possibility of a clash between a rising and an established power that lies behind the oft-used parallel between contemporary East Asia and early 20th-century Europe, in which the Senkakus play the role of Sarajevo.

Seas of troubles

Tensions are not at that level. Japan’s constitution bans it from any military aggression and China normally goes to great lengths to stress that its rise—unlike that of Japan in the 1920s and 1930s—will be peaceful. But the neighbours are nervous, especially as the establishment of the ADIZ appears to match Chinese ambitions in the South China Sea.

Chinese maps show what is known as the “nine-dash line” encompassing all the South China Sea. In the wake of the global financial crisis, perhaps believing its own narrative of Chinese rise and American decline, it began to overreach in its dealings with its neighbours. It sent ships to disputed reefs, pressed foreign oil companies to halt exploration and harassed American and Vietnamese naval vessels in the South China Sea. These actions brought a swift rebuke from America’s then secretary of state, Hillary Clinton, and China appeared to back off and return to its regional charm offensive. Some observers say that the government is using the ADIZ to establish a nine-dash line covering the East China Sea as well. They fear China’s next move will be to declare an ADIZ over the South China Sea, to assert control over both the sea and the air throughout the region.

Whether or not China has such specific ambitions, the ADIZ clearly suggests that China does not accept the status quo in the region and wants to change it. Any Chinese leader now has an excuse for going after Japanese planes. Chinese ships are already ignoring Japanese demands not to enter the waters surrounding the disputed islands.

What can be done? Next week Joe Biden, America’s vice-president, arrives in China. The timing may be uncomfortable, but it is fortuitous. Mr Biden and Mr Xi know each other well: before Mr Xi became president, he spent five days in America at Mr Biden’s invitation. Mr Biden is also going to South Korea and Japan.

America’s “pivot” towards Asia is not taken very seriously there: Mr Obama is seen as distracted by his domestic problems. Mr Biden could usefully make clear America’s commitment to guaranteeing freedom of navigation in the region. Japan and South Korea, who squabble over petty issues, need to be told to get over their differences. As for China, it needs to behave like a responsible world power, not a troublemaker willing to sacrifice 60 years of peace in north-east Asia to score some points by grabbing a few windswept rocks. It should accept Japan’s suggestion of a military hotline, similar to the one that is already established between Beijing and Washington.

The region must work harder to build some kind of architecture where regional powers can discuss security. If such a framework had existed in Europe in 1914, things might have turned out differently.