The Chinese navy has been throwing its weight around in East Asia. A US Navy commander asks how much longer the US can do anything about it.On the night of March 26 the Cheonan, a South Korean Navy corvette patrolling in the Yellow Sea, mysteriously erupted in a cataclysmic explosion and sank to the bottom. The ship was just off Baengnyeong Island, near the Northern Limit Line, which is the armistice separation line between North and South Korea. Of the 104 crew on board, only 58 survived. Salvage operations confirm the ship was struck by a North Korean heavy torpedo...