When a U.S. guided missile destroyer sailed within 12 nautical miles of a Chinese-claimed island in the disputed South China Sea last month, it set off a volley of protests from Beijing.
“The U.S. is challenging and provoking the new maritime order by wielding its military power,” Foreign Ministry spokesman Lu Kang said. China’s defense ministry said it would bolster its capabilities in the area as needed.
The resumption of U.S. “freedom of navigation operations” in the South China Sea — with three since October after a three-year hiatus — reflects the global focus on a maritime route that carries $5.3 trillion of global trade a year. Tensions between China and Southeast Asian nations over the waters sit at the center of a rivalry between the U.S., overseer of the region’s security network for decades, and a rising China intent on becoming the region’s dominant power.

http://www.bloomberg.com/news/articles/2016-06-01/south-china-sea-state-of-play-china-and-u-s-gear-up-for-ruling