China's establishment of an administrative base and, just last week, a military garrison in a tiny city in the Paracel islands has upped regional tensions. Elias Groll explains why:

[W]hat exactly is at stake in the South China Sea? For starters, as many as 213 billion barrels of oil -- more than the reserves of any country except Saudi Arabia and Venezuela -- according to a 2008 report from the U.S. Energy Information Administration. As a result, China, Vietnam, the Philippines, Taiwan, Malaysia, and Brunei are engaged in fierce jockeying over the rights to what at first glance are not more than a handful of rocks.

Jim Holmes conveys the context of China's strategic positioning: