When West Capella, a drill ship hired by Malaysia’s national oil company Petronas to survey for oil in the South China Sea completed its activities last week, the US Navy ship Gabrielle Giffords left its base in Singapore to sail past it. It was the third time in recent weeks that the United States had conducted “presence operations” in the resource-rich waters, which has been the site of renewed tensions between China and its Southeast Asian neighbours over the latter’s oil exploration and…