China believes it can handle American warship visits to the South China Sea without triggering a disastrous (especially for China) war by quietly mobilizing a growing fleet of civilian cargo and fishing vessels. These unarmed ships are used, usually in groups, to block the moment of unwelcome foreign commercial or military ships. This Chinese “naval militia” has a numerical advantage because the U.S. Navy only has 55 warships assigned to the West Pacific while the China has 116 warships assigned to its southern (mainly the South China Sea) fleet plus 200 large (over 500 tons) seagoing coast guard vessels in the area. Increasingly China is calling in the naval militia, which apparently quietly pays participating ships for their services. This is what intelligence analysts concluded after examining the use of this militia over the last few years. Most of these Chinese civilian ships had no legitimate reason to be where they were when they “encountered” foreign military or commercial ships “trespassing” in the areas of the South China Sea that China claims as sovereign territory. There appear to be over a hundred civilian ships associated with this militia program.
China uses navy, coast guard and commercial ships to aggressively confront American (or any other) ships that come close to Chinese ships or claimed territory in the South China Sea. This sort of aggressiveness has not been encountered by American warships on such a scale since the Cold War when Russian warships would risk collision in what American sailors came to call "Chicken Of The Sea" incidents. These Cold War incidents, usually involved Russian ships harassing American ships by moving very close, or even on a collision course. This has been improved on by the Chinese who also use coast guard and civilian vessels.
During the Cold War this was all for the purpose of interfering with U.S. intelligence operations, especially those off the Russian coast. Earlier in the Cold War Russian warplanes would fire on American intelligence gathering aircraft, shooting some of them down. This sort of thing declined when the U.S. quietly informed the Russians that American warships and combat aircraft would aggressively return fire. By the end of the 1960s, this aggressive activity diminished to the point where it was considered a minor nuisance and even that was eliminated by a 1972 treaty.
The same pattern is playing out with the Chinese but for the last few years the Chinese have continued to protest American intelligence gathering activity so close (up to 22 kilometers from Chinese territory, an area that is considered “territorial waters”) as well as the South China Sea operations. Long term China believes it can win this war of wills. China appears to have examined the Russian Cold War tactics and improved on them and so far the improvements have worked.
Naval militias are nothing new and are an ancient tradition. What is different with the Chinese version is that it is stealthy and used for operations the Chinese government would prefer to deny.