>> hill: good evening. katie is off tonight. muammar qaddafi's inner circle continues to shrink. first, his foreign minister defected last night. and then today, his u.n. ambassador quit while in egypt. just the same, qaddafi's military, though decimated by allied air strikes, is still pounding rebel forces. driving them further east away from key oil towns. one rebel leader compared qaddafi to a wounded animal, one that's more dangerous than a healthy one, which once again raises the question-- just what should the u.s. do moving forward? david martin begins our coverage. >> reporte...