that differentiates him from his other republican rivals in this race. national security has been a centerpiece of his campaign. but he's not the only candidate who is trying to get a leg up. others are as well, carly fiorina addressed this on facebook as well. this is what she had to say earlier today. she said "of course north korea would conduct a nuclear test after watching iran willfully violate an agreement they just made without consequence of any kind from this administration. north korea is yet another hillary clinton foreign policy failure. america cannot lead from behind." so clearly each candidate believes they can get a leg up on this issue if they try to espouse a more hawkish foreign policy view, and clearly that is what marco rubio is doing right now here in marshalltown. we'll see if it works, carol. >> manu raju reporting live from iowa this morning. still to come in the "newsroom," birther deja vu. trump says cruz could have a big problem when it comes to his canadian roots.