China has accused a Philippines coast guard ship of deliberately colliding with a Chinese vessel in the latest flareup of tensions over disputed waters and maritime features in the South China Sea. China is rapidly expanding its military and has become increasingly assertive in pursuing its claim to virtually the entire South China Sea which is crucial to international trade. The tensions have led to more frequent confrontations, primarily with the Philippines, whose security the U.S. is treaty-bound to ensure. Does the whole Southern China sea belong to China ?