defense secretary william perry, one of the most respected voices on informed nuke lee deterrence, tweeted this. i want to read it to you. dr. perry saying, nuclear deterrence is only effective if threats are deemed credible. bluster hurts our national security posture. words from someone who, out of office for many years, remains one of the most credible voices, as i say, on informed nuclear deterrence, wolf? >> very interesting. barbara, thank you. barbara starr at the pentagon. >>> let's talk more about the breaking news. we are joined by our global affairs correspondent elise lachl it and ripley who has done extensive reporting in north korea, 13 times. based on your experience -- you are joining us now from beijing -- what is kim jong-un's end game now? how might he respond to president trump's warning of fire and fury? >> well, the end game is to have an icbm with a miniaturized nuclear warhead, a whole arsenal of them to serve as a deterrent against the united states because north korea has told its citizens for decades that they're under the imminent threat of invasion. as for his direct response to this rhetoric fr