Obama speech aims to reassure a nervous nation

President Barack Obama will try to reassure a nervous nation on Sunday that he has a plan to defeat the fast-evolving threat of terrorism, as fears multiply of ISIS attacks on the homeland and public trust in his handling of the threat dipping to record lows.

Obama's rare 8 p.m. ET Oval Office address reflects growing anxiety that the global showdown with the extremist group has now spread to U.S. soil following a mass shooting in San Bernardino, California, that authorities are treating as terrorism.