Last October, when the American destroyer USS Lassen sailed by Subi Reef, an artificial island built by China in the South China Sea, a number of Chinese merchant ships and fishing boats maneuvered around it, apparently having anticipated its approach. The Lassen was on a freedom of navigation operation, meant to demonstrate the United States’ commitment to maintaining open access to the area, much of which China claims as its own. China was using an unusual resource to broadcast its opposition to the trip: ships that appeared to be crewed by civilians, but in all likelihood were actually controlled by state-sponsored forces taking orders from China’s military.
To promote its disputed claims in the South China Sea, China is increasingly relying on irregular forces such as these, which together form what China calls its maritime militia. In recent years, maritime militia units have played important roles in a number of encounters and skirmishes in international waters: in 2012, for example, they participated in China’s seizure of the Scarborough Shoal from the Philippines, and in 2014, they helped China repel Vietnamese ships from an oil rig that China had stationed near the contested Paracel Islands.
The militia units help China take the initiative in encounters with foreign forces.
The militia represents a useful tool in China’s plan to bloodlessly press its maritime claims, since its frequently civilian appearance allows Beijing to deny its involvement in encounters such as last October’s and exploit the U.S. Navy’s rules of engagement, which limit the actions U.S. ships can take against civilian vessels. Despite its potency, the maritime militia is the least understood of China’s sea forces, and so far, the U.S. government has not acknowledged its existence in public reports or major official statements. That should change. By showing Chinese leaders that it is wise to their game, Washington could discourage Beijing from using the militia even more assertively than it has so far—a crucial step in