jake tapper. the "the lead" starts roo right now. >>> thanks, brooke. ted cruz, warns republicans if trump wins in iowa he'll be unstoppable. i'm sure the donald might agree. the "the lead" starts right now. brand-new poll showing donald trump out to his largest lead, doubling ted cruz nationwide, as the race in the hawkeye state comes down to the wire. >>> more dangerous than isis. a new report saying a terrorist group with al qaeda ties could be working on another 9/11 while the u.s. puts all its focus on destroying isis. >>> plus -- possibly arm the, definitely dangerous, one of them being compared to hannibal lector, the manhunt for three inmates after a soing jail break. did they have help on the inside? >>> good afternoon, welcome to "the lead." i'm jake tapper. we'll start with politics lead, with six days left until the iowa caucuses, ted cruz and donald trump cranking up war of words as they battle for toll billing in the state. going after conservatives and evangelical voters with a religious fervor. trump trouted out an endorsement from jerry