Q. & A.: Rory Medcalf on the Meaning of China's Air Defense Zone China's declaration of an air defense zone in the East China Sea has prompted concern among some neighbors who fear it will be used to bolster territorial claims. Japan in particular has questioned China's intentions as the zone encompasses a group of small islands claimed by both countries as well as by Taiwan. Japan now administers the islands, known as the Diaoyu in China and the Senkaku in Japan, but over the past year China has been escalating its challenge to Tokyo's control. After the Chinese announcement, the United States flew B-52 bombers through the zone, ignoring Beijing's demands that all aircraft submit flight plans. But the Federal Aviation Administration is advising commercial airlines to comply with the new identification requirements out of concern for safety. Vice President Joseph R. Biden Jr. of the United States, who is on a weeklong trip to China, Japan and South Korea, says the zone raises tensions and the risk of mishap, and is expected to outline the United States" position to Chinese President Xi Jinping in Beijing. Rory Medcalf, director of the International Security Program at the Lowy Institute for International Policy in Sydney, argues that China miscalculated and that the United States should use the moment to persuade China and others to establish mechanisms in the region to minimize the risk of an incident that could trigger a conflict. The following are edited excerpts from an email interview with Mr. Medcalf: China has described the establishment of this zone as a normal step that has been taken by many other countries. What do you think Beijing hoped to accomplish through declaring this air defense identification zone, or A.D.I.Z.? Presumably the Chinese leadership - and we have to assume this comes from the top - wanted to apply renewed pressure on Japan in the islands dispute. Japan's pre-existing A.D.I.Z. may have been seen as giving it an excuse to scramble fighter aircraft every time it detected a Chinese Air Force foray into that space. With its own zone, China now may try to claim a bit more moral high ground next time - and if there is a dangerous incident, it will say there was fair warning, and reserve the right to escalate. Do you think China is accomplishing what it set out to achieve with this zone? Do you think other zones could follow, encompassing contested areas like Taiwan or the South China Sea? Diplomatically, China has miscalculated. I doubt it expected to spook South Korea, Australia, the E.U. and others as well as the United States and Japan on this issue. It would much prefer to diplomatically isolate Japan, and it has set back its chances of doing that. But time will tell whether the short-term diplomatic pain will give China the long-term strategic gain it wants. Much will depend on whether the United States, Japan and others can be smart, determined and coordinated in the way they respond. There may also be a long-term calculation by China that as other countries and their civilian airlines get used to complying with the zone, it will lead to a kind of incremental acceptance of Chinese authority in the air and at sea in this and other contested spaces in East Asia. The same thing is happening with Chinese naval activities. A recent major exercise involved a fleet sailing between Japanese islands to maneuver east of Taiwan, as proof that China had permanently broken through the so-called first island chain. This is not outright aggression; it is something more subtle and difficult to handle than that. The way the rest of the region responds now will also have some influence on what China does next. It has publicly foreshadowed more such zones in the future, perhaps extending into the disputed South China Sea. Tokyo has advised Japanese airlines not to follow the rules of the zone, while the United States government has said American airlines should. How would you rate these responses? Is Japan putting sovereignty over safety? Is the United States being too cautious? No private airline can be expected to add even the slightest degree of risk or uncertainty for its passengers in the name of geopolitics. But the United States is being careful. Its advice to airlines is offset by the fact that it has taken the lead in ignoring China's A.D.I.Z. with some of the most totemic military aircraft at its disposal. There is still some uncertainty about what exactly such a zone is. How do you define it? It is not a territorial claim. Instead it's an area of international airspace over a which a particular country asserts the right to identify air traffic headed for its territory, including in order to distinguish potential threats from foreign military aircraft. And in the case of the new Chinese A.D.I.Z., there's a demand that all aircraft within the zone - military or civilian - identify themselves and provide flight path information, even if they are just in transit. Moreover, China seems to reserve the right to challenge and give direction to aircraft in the zone. You've said that such a zone isn't an inherently bad thing. What are positive aspects of such an A.D.I.Z.? Many countries established these zones during the Cold War, including the United States, Japan and South Korea. In theory, they can help to keep the peace by providing early warning for defensive purposes - assuming of course that all countries respect each other's zones. China's implementation of the zone, however, has raised questions. What do you see as the chief issues with how China has gone about this? China has as much right to an A.D.I.Z. as any other country. And China's efforts to push foreign aerial surveillance far from its shores are not surprising. But the way China has gone about its recent announcement has been destabilizing. The biggest problem is that China's new zone overlaps Japan's own longstanding A.D.I.Z., especially over the contested Senkaku/Diaoyu islands, and this adds to already serious security tensions over that maritime territory. There's also a lack of clarity over what China will do to enforce the zone, with implicit threats to take action against foreign military aircraft that do not comply. The United States, Japan and South Korea have now all tested the zone by sending military aircraft on patrols without informing China. What were they hoping to accomplish? Do you see these moves as prudent? Potentially dangerous? Something else? In the circumstances, these three countries did what they had to do. Unless they were ready simply to accept this new increment of Chinese authority over regional airspace, they had to act soon to show that in their view the status quo had not changed. For the United States, it was especially important to do something tangible to reassure its allies - in fact, China has given the Obama administration a chance to show that the rebalance to Asia remains real. How do you judge Beijing's initial reaction to the U.S. overflight, that it monitored and identified the B-52 bombers and retains "the ability to implement effective management and control of the airspace?" Did China blink? The B-52 flights certainly caused embarrassment, forcing Chinese officials and newspaper editorials into some fairly excruciating dissembling and policy clarifications. Suddenly, the line was that the flights had been "monitored" from afar, and that was enough to preserve national honor. The cautious Chinese response received some criticism at home, that China's ruled were ignored by other countries. Is there a danger that the Chinese leadership will be pushed into more aggressive steps? It would make sense for the United States and its allies not to play up any perceived Chinese passivity or backdown - or even to claim that China does not have the military capability to patrol the zone. The goal right now should be to use the whole controversy as a springboard to start a new dialogue about risk-reduction in the air and at sea. That should be the focus of Vice President Biden's visit to the region this week. He should be saying to Xi Jinping: "You say you want to create predictability and avoid unintended conflict. So do we, and so does Japan. Let's build rules of the road for military activities at sea and in the air, including operational hotlines to prevent or manage incidents. China announced late Thursday that it has sent military aircraft to patrol its new air defense zone. With the United States and its allies testing this zone, and China patrolling it, is there a danger of some sort of incident between military aircraft, either intentional or accidental? There was a risk already, and that risk is now heightened - especially if there is anything but absolute discipline in the way the Chinese Air Force goes about interpreting the new rules. Tension has become the new normal in East Asian waters, and now in the air, too.