escaped from prison. trump says the u.s. will invite him to become a citizen. >> i think he has hijacked the debate. i think he's a wrecking ball. >> i don't know if he's helping or hurting but he's a candidate. >> reporter: wanting to build a wall between the u.s. and mexico. >> it's common sense. we need to secure the border. >> reporter: tied with jeb bush for first place among republicans with almost 16% support. but 40% of republicans say they would never vote for him. >> that's tracy pots reporting. to vienna secretary of state john kerry and other foreign leaders are still trying to hammer out a deal with iran. it remains to be seen if a deal can be struck by today's deadline or if there will be a fifth extension. chief foreign affairs correspondent andrea mitchell has the latest. >> reporter: after three missed deadlines and 16 days of