issue we have to address just that because that is what is pressing immediately. if you quickly, robert, see the way the iran nuclear deal has been debated, again, what can we learn from that to apply perhaps to north korea who already have these nuclear weapons? >> you are right, your final point is spot on because north korea is a much more mature nuclear program. i think the decoupling piece is important. if you look at the structure of our debate on the hard cases of iran and north korea, it goes back to the post-9/11 period where there was a divide in our debate over how to address these hard cases, so-called rogue states, should arid objective be to change their behavior or should it be to change their regime? for those who focus on regime change, it's on understandable because they say the danger arises from the character of the regime and changed behavior lot take you there if that regime stays in power, the character of the regime is unchanged, and that is from where the