make foreign policy happen with north korea or some other nation. that is a different kind of a conversation and the assumption there is that there are some hours, days, or even weeks to try and fashion a response. i believe that is what he was really getting at there. >> convex now to my historian, julian zeleny. is it common to hear the top u.s. nuclear commander speak about this in the hypotheticals of an illegal order from the president? >> no, it's not. i think there has been an assumption at some level that the president is rational and the president will have some sense of both the rinsks and threats of launching a nuclear war, so some of this discussion is very particular. it's about the current president, rather than the president in general. but it does come after many decades where congress has seeded authority to the president on matters of war, where there has been many warnings we can't have so much power under the hands of a president and particularly with nuclear weapons.