On November 23, the People’s Republic of China announced a new air defense identification zone (ADIZ) covering a large swath of the East China Sea. Most importantly, it covered the airspace over the disputed Senkaku islands. This move, effectively escalating tensions in Asia, led the United States to order two B-52s to fly over the Senkakus, clearly asserting the right of American aircraft to transit this sensitive area.

The Chinese announcement that sparked this crisis not only covered the disputed islands but extended over an area of the East China Sea itself that is claimed by both Japan and China as part of their respective Exclusive Economic Zones (EEZs). Beijing stated that aircraft entering the ADIZ would be required to file flight plans in advance, identify themselves through radio and transponder communications, and obey instructions emanating, ultimately, from the Chinese Ministry of National Defense. Soon afterwards, the Chinese announced that they had mounted their first aerial patrol of the ADIZ.

The creation of an ADIZ is not the same as creating an aerial exclusion zone, or effectively creating sovereign airspace; rather, it constitutes a buffer. Because there is no agreed upon international standard for how ADIZs are established, China’s actions were consistent with international practice.

The problem, however, is that China’s creation of this zone gravely heightened regional tensions. The Chinese claims overlap significantly not only with Japan’s ADIZ but also with part of South Korea’s ADIZ. This creates the real possibility of overlapping airspace where both Chinese and Japanese (or Chinese and South Korean) fighters could find themselves in close proximity, each believing they are operating within their own ADIZ. The chances of a mishap would increase radically.

From the Chinese perspective, this is not necessarily a bug; as Chinese interlocutors have indicated in the past, the best way to avoid miscalculation is for others to avoid disputed areas. As important, the ADIZ appears to follow China’s EEZ claims, reinforcing China’s claims to extensive portions of the East China Sea.

Chinese demands regarding other countries transiting their EEZs are much closer to the behavior typically accorded territorial waters, so acceding to China’s ADIZ claims are likely to constrain future air operations, just as China would like to limit other states’ maritime activities in their EEZ.

In short, the Chinese announcement of an ADIZ is an attempt, through legal and psychological warfare, to reinforce its claim to most of the East China Sea.

For this reason, the Obama Administration’s sharp, prompt response was essential. The decision to dispatch two B-52s into the Chinese ADIZ, without prior notification, was exactly the right one, as it served clear notice to Beijing that its effort would not be supinely accepted. As important, it clearly indicated to Tokyo, and other U.S. allies, that the U.S. remains firmly committed to its treaty obligations (which in this case extend to the Senkaku islands).

However, it is unlikely that the situation has been resolved. Beijing clearly believes that it can act with impunity, with little concern about antagonizing its neighbors. And having declared an ADIZ, without sufficient pushback from the U.S., it is likely to attempt to enforce it in the future. The U.S. should continue to physically assert its understanding of its own rights in that airspace to prevent any misunderstanding of its resolve.