By RAND Project Air Force for CASI
/ Published November 22, 2017
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In November 2013, the People’s Republic of China (PRC) declared an air defense identification zone (ADIZ) in the East China Sea (ECS). Even after the immediate backlash from the United States and Japan, the zone’s legitimacy, legality, implementation, and purpose have remained the subjects of debate.
Although ADIZs are not governed by international law, differences in U.S. and Chinese regulations with respect to the inclusion of contested territory within the ADIZ and the identification of foreign aircraft traveling through the ADIZ but not entering territorial airspace are points of contention that have the potential to destabilize the region. In particular, the PRC interprets the United Nations Convention on the Law of the Sea as permitting coastal states to restrict foreign military activities within and above their Exclusive Economic Zone has created cause for concern, and PRC ADIZ regulations appear to reinforce this interpretation.
While the PRC has not done much to publicize whatever measures it may have undertaken to enforce its ADIZ as of early 2017, it may never have intended to do so with much vigor, which reinforces that its establishment was largely political—a strategic surprise, but what it may perceive as a proportional response in a region filled with ADIZs.
U.S. observers appear particularly concerned about the implications of the PRC’s ECS ADIZ for a potential PRC ADIZ in the South China Sea (SCS), where China is entangled in numerous maritime territorial disputes in a small space and where civil air travel is increasing dramatically, creating a complex air environment for U.S. pilots. Responding to foreign aircraft, practicing real-time hand-off by air defense entities, and interacting with airborne command and control aircraft all have the potential to enhance the capabilities of Chinese aviators.
This report explores the legal and administrative groundwork China has laid for its ADIZ in the ECS and assesses the PRC’s potential to establish an ADIZ in the SCS as part of its ongoing efforts to bolster territorial claims there. The PRC’s reclamation and militarization of its claims in the SCS have created new “facts on the ground” and represent the availability of a much broader range of policy options and responses there as compared to the ECS. The other claimants have responded to China’s actions with political and military responses of their own, which further complicate the operational environment. This report contrasts the considerations that drove the decision to declare an ADIZ in the ECS with the political conditions in the SCS and explores the options for declaring an ADIZ there from China’s perspective.