The Chinese government’s November 23 announcement of an Air Defense Identification Zone (ADIZ) over a large segment of the East China Sea and a cluster of small, uninhabited islands, called Senkaku by Japan and Diaoyu by China, poses a fresh and difficult challenge for the United States. The islands are administered by Japan but claimed by both China and Japan, which view them as a redoubt in a vast stretch of ocean with promising oil and natural gas reserves. Until now, Washington has pursued an ambiguous policy on the islands, asserting neutrality on the question of their ultimate ownership (thus pleasing the Chinese) while reassuring Tokyo that it would assist any Japanese forces that come under attack in the area in accordance with the U.S.-Japan Mutual Defense Treaty of 1954. Although this stance was once deemed sustainable -- there appeared to be little chance that the United States would ever be called upon to honor its treaty obligations -- that day is over.
It is not unusual or necessarily provocative for coastal and island states to declare ADIZs over their offshore territories. China’s action in the East China Sea, however, is different. For one thing, Beijing did not discuss its plans with any of its neighbors -- several of which have already established their own ADIZs in the area -- or with the International Civil Aviation Organization, an agency within the United Nations tasked with setting air-safety regulations. More important, China extended its zone over the disputed Senkaku (Diaoyu) Islands and into an ADIZ already being enforced by Japan, which was an implicit challenge to Japan’s claims of sovereignty over the islets. To eliminate any doubts about its intentions, Beijing also announced that all aircraft entering the Chinese ADIZ must identify themselves, report their flight plans, and obey any instructions relayed to them by the Chinese Ministry of Defense, warning that a failure to do so could provoke “emergency defensive measures.” Since then, the Chinese have already begun