On April 22, 2014, navy chiefs from twenty countries, including the United States, China, Japan, the Philippines, South Korea, and Vietnam, attended the Western Pacific Naval Symposium in Qingdao, China, and approved a nonbinding agreement setting forth rules governing unplanned encounters at sea. (1) The Code for Unplanned Encounters at Sea (CUES) "offers safety measures and a means to limit mutual interference, to limit uncertainty, and to facilitate communication when naval ships or naval aircraft encounter each other in an unplanned manner." (2)
The agreement comes at a time of rising discord in the Pacific region. Tensions have escalated since China's unilateral implementation in November 2013 of an air defense identification zone (ADIZ) (3) over a large swath of the East China Sea that contains a chain of islands that both China and Japan claim as their own territory. (4) The Japanese government purchased the islands--known as Senkaku in Japan and Diaoyu in China--from a private Japanese landowner in September of 2012. The new Chinese ADIZ also overlaps with South Korea's own ADIZ, including the airspace above a submerged reef--known as Ieodo in South Korea and Suyan Rock in China--to which both countries lay claim. (5) South Korea responded by unilaterally expanding its ADIZ to include airspace in the East China Sea that is also claimed by Japan and China. (6) The South China Sea has likewise "been the subject of competing territorial and maritime claims for decades," with sharp tensions resurfacing recently over the international legality of China's "nine-dash line" assertion of maritime jurisdiction in the region. (7)
In response to this welter of counterclaims and regional tensions, CUES is intended to "offer a means by which navies may develop mutually rewarding international cooperation and transparency and provide leadership and broad-based involvement in establishing international standards in relation to the use of the sea." (8) CUES lays out two protocols for communication among vessels and aircraft, one "by sound, light and flags (which, in reality, has already been agreed through the 1972 International Regulations for Preventing Collisions at Sea (COLREGS) that applies to all vessels)" and the other "by radio (in English, with designated call-signs, and clear procedures for information exchange)." (9)
Because of the nonbinding nature of the agreement (10) and its apparent inapplicability to territorial waters, (11) some observers have suggested that it may not change naval behavior in any...