China’s military imposed a destabilizing air defense zone over the East China Sea without consulting the United States, and top Pentagon leaders said Wednesday there have been no contacts with their Chinese counterparts since the zone was set up Nov. 23. Defense Secretary Chuck Hagel and Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, said at a press conference at the Pentagon that the Chinese air zone is destabilizing the region. However, both leaders declined to urge China to roll back the air defense identification zone, or ADIZ, as Japan’s government has demanded of the Chinese. The lack...