south korea. let's begin with barbara starr over at the pentagon. any indication of who might have caused the internet in north korea going down? what's the u.s. say? >> well, right now, wolf, the obama administration isn't saying anything. very interesting. the white house, the state department, the pentagon, all quiet about this. but you will recall that the administration said it would respond to north korea's hacking of sony, it would respond at a time and place of its choosing, and that response may not be made public. it may be very secretive. and that's leading some of the speculation around the world tonight that the u.s. may be behind this hacking attack against north korea, retaliation. a lot of people say maybe not. that the u.s. wouldn't want to do something so overt. you can't always measure north