North Korea does not have nuclear bombs or squadrons of bombers, but we cannot take for granted that the North will invest in the safest designs for its warheads or missiles. It is unlikely, but conceivable, that a warhead, jettisoned from a missile that explodes due to a fueling mistake, could detonate. A nuclear detonation on North Korean soil would be hard to cover up, and Kim Jong-un would undoubtedly deflect blame by accusing the Americans, South Koreans, or Japanese of sabotage or an attack, sparking a military crisis that could be uncontrollable.

All this raises the question of accountability. As retired Air Force Lieutenant General James Kowalski, a B-52 pilot and the former deputy commander of US Strategic Command, put it to me in an interview: “Who is going to be the guy who goes to Kim Jong-un and tells him he has a problem with his nukes?” Absolute trust is required between leaders and those charged with maintaining and operating nuclear weapons. It is hard to imagine that existing among Kim’s circle of terrified sycophants.