“He is very rational within his own context — Kim Jong Un, that is.”

Considering the long-running battle of taunts and provocations between the North Korean leader and President Trump, Lisa Monaco had to make such a clarification. “[Kim] is quite rational in trying to maintain the continued existence of the regime,” Monaco told me in the latest episode of “Cape Up.” “That means continuing to have this nuclear capability as his hedge against anybody trying to overthrow that regime and to stop his leadership.”

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Monaco was the homeland security adviser to President Barack Obama. Dangers foreign and domestic occupied her time in the White House. And the danger posed by Kim remains clear. “North Korea … is probably the most urgent national security issue,” Monaco said. “And that is owing to the very, I think, erratic and volatile situation we see in the escalation of the rhetoric on both sides.” More to the point, she said, “It is concerning when you have a discussion about nuclear weapons that is done in this kind of volatile fashion.” The terror unleashed by a missile false alarm over the weekend only served to emphasize Monaco’s point.

I talked with Monaco about other homeland security threats facing the country. A bright spot? “We have done a very good job of reducing that threat of a 9/11-style attack,” she told me during the interview at the WNYC radio studios in Lower Manhattan. A growing concern? The cyberthreat. It “has evolved at a pace and a scale and a sophistication over the last several years,” Monaco explained, “that has caused the cyberthreat actually to leap ahead of the terror threat … in terms of the complex threats that we face.”

What you might not know about Monaco is that she is a former prosecutor who also served as a chief of staff to Robert S. Mueller III when he was director of the FBI. “He is a patriot and a public servant through and through,” Monaco said of the man leading the investigation into Russian interference in the 2016 election and now being vilified by many Republicans, “and he is somebody who is not driven by any partisan or political motive in anything that he’s ever done.” She added that “he is somebody who believes deeply in the institution of the Justice Department … of maintaining the independence of that investigative and prosecutorial function of the Justice Department.”

Listen to the podcast to hear Monaco talk more about the impact of Trump’s tweets on foreign policy in Asia and on America’s standing in the world. But you’ll want to hear what she has to say about the pace of Mueller’s investigation and what the special counsel knows about former national security adviser Michael Flynn, who pleaded guilty last month to lying to the FBI.

“The paper record that we have as a public with regard to Flynn’s plea deal and what he has signed up to admitting,” Monaco said, “I believe that’s a fraction of what he has told the Mueller team and what they know.”

“Cape Up” is Jonathan’s weekly podcast talking to key figures behind the news and our culture. Subscribe on Apple Podcasts, Stitcher or wherever else you listen to podcasts.