U.S. military sent a guided missile destroyer into disputed area, the South China Sea. This would be a President Obama's warning to China. Chinese government has been building military facilities on the landfill reefs where only China claims as their own territories.
The Obama's decision was too late to suppress Chinese desire for expanding their territories for the water. I can't understand his slow action for the controversial Chinese activities of the South China Sea. Vietnam and other nations were trying to prevent the China's behavior, but the president didn't do anything for it.
It's important to put pressure on China over territorial matters. Otherwise, they will continue to expand their territories by the power.