Scarborough Shoal: A Red Line for the Philippine-U.S. Military Alliance?
As U.S. defense secretary Ashton Carter visited the Philippines at the end of the annual Balikatan military exercises between the Philippines and the United States, anxiety was quietly building over the possibility that China would create a new artificial island on Scarborough Shoal, very close to Manila. Such an undertaking would come as the Philippines experiences a transition in political leadership via presidential elections in May. Despite hopes in Manila, Carter did not offer an official assurance of U.S. assistance in preventing Scarborough from being permanently taken over by China, though his visit, which included a trip with Philippine defense secretary Voltaire Gazmin to a U.S. aircraft carrier transiting the South China Sea, was intended to signal Washington’s commitment to the alliance.
The general U.S. policy of neutrality on questions of sovereignty over South China Sea land features was originally established in the 1930s in response to Japan’s pre-war annexation of the Paracel and Spratly islands. But Scarborough Shoal was treated separately and very differently from those island groups up until the 1990s. Unlike the Paracels and Spratlys, Scarborough was among the territories transferred by the United States to the Philippines upon the latter’s independence, though the shoal was not widely known. The 1900 Treaty of Washington between Spain and the United States clarified that any and all territories administered by Spain as part of the Philippine Islands, even if they were located outside the original 1898 Treaty of Paris lines circumscribing the Philippine archipelago, were ceded to Washington. The United States took over Spain’s administration of Scarborough for purposes of safety of navigation, fishing, research, search, rescue, and salvage activities. In 1938, upon official inquiries, the U.S. Department of State recognized that the United States acquired title to the shoal from Spain on the basis of the 1900 treaty, and subsequently allowed Scarborough’s transfer to the Philippines with concurrence of the Secretary of the Navy and the Secretary of Commerce. (See primary documents)
The Philippines took over the shoal’s administration in 1946 upon its independence. After the Philippine Navy twice destroyed smugglers’ bases on the shoal in 1963, a 20-nautical-mile Naval Operating Area was established around it, turning Scarborough into a gunnery range and extension of U.S. military bases in the Philippines. The security perimeter kept out any further incursions by private parties, but seasonal fishing and occasional surveys and scientific research were allowed. The area was regularly used by Philippine and U.S. military forces openly and publicly until the U.S. bases closed in 1991. Only afterward did China actually take concrete action to assert its long-dormant paper claim to the shoal, beginning with the issuance of amateur-radio licenses to hobbyists in 1994. These later intensified into the assertion of traditional fishing rights into the early 2000s that eventually grew into a claim based on historic rights and title, and finally culminated in China’s coercive exclusion of all Philippine fishing and law enforcement activities from the shoal since 2012.