Militarily, they represent a thin crust on China’s A2/AD system. Under certain conditions this crust could disrupt U.S. freedom of action, but it won’t be hard for the United States’ Air Force and Navy to punch through.
The four largest military installations in the SCS have extensive facilities for the operation of military aircraft. This includes advanced fighters, but more importantly patrol, electronic-warfare and advanced early-warning aircraft. The ability to use these airfields effectively extends the reach of China’s A2/AD bubble, enabling the transmission of targeting data to missile launchers at sea and in mainland China. The fighter aircraft themselves serve to make the skies over the SCS even more lethal than they otherwise would be, as well as threaten U.S. ships at a distance with cruise missiles.
China has built some islands in the South China Sea. Can it protect them?
During World War II Japan found that control of islands offered some strategic advantages, but not enough to force the United States to reduce each island individually. Moreover, over time the islands became a strategic liability, as Japan struggled to keep them supplied with food, fuel and equipment. The islands of the SCS are conveniently located for China, but do they really represent an asset to China’s military? The answer is yes, but in an actual conflict the value would dwindle quickly.
China has established numerous military installations in the South China Sea, primarily in the Spratly and Paracel Islands. In the Spratlys, China has built airfields at Subi, Mischief and Fiery Cross, along with potential missile, radar and helicopter infrastructure at several smaller formations. In the Paracels, China has established a significant military installation at Woody Island, as well as radar and helicopter facilities in several other areas. China continues construction across the region, meaning that it may expand its military presence in the future. The larger bases (Subi, Mischief, Fiery Cross and Woody Island) have infrastructure necessary for the management of military aircraft, including fighters and large patrol craft. These missiles, radars and aircraft extend the lethal reach of China’s military across the breadth of the South China Sea.