Analysts Puzzle Over Pyongyang's Motives For Shelling

Analysts are trying to figure what could have motivated North Korea to shell a South Korean island in the Yellow Sea on Tuesday during military exercises by the South. Among the theories: the attack was designed to bolster the credentials of North Korea's young heir apparent, Kim Jong-un; North Korea and China want to make the Yellow Sea disputed waters to discourage the U.S. military presence there.