dr. john lapook. high stakes at the u.s. supreme court. jan crawford previews three days of arguments over health care reform. and box office bull's-eye. "the hunger games" sets a record. lee cowan hears from the young fans who just can't stay away. >> i wasn't sure if i was shaking because i was cold, excited or on a sugar high. captioning sponsored by cbs this is the "cbs evening news." >> glor: good evening, everyone. i'm jeff glor. there was hope that with new leadership in north korea there would be a new approach to its weapons program, but the north's new threat to defy a missile test ban brought strong words from president obama today. the president is visiting south korea for an international conference on nuclear security, and white house correspondent bill plante is there, as well. >> reporter: the president is in south korea for a summit aimed at keeping nuclear material out of the hands of terrorists. but the overriding question here is how to deal with a nuclear armed north korea. >> north korea will achieve nothing but threa