The United States is rightly worried that a strange and callow leader controls North Korea’s nuclear arsenal. North Korea should reciprocate this worry. Yes, a 70-year-old can be callow if he speaks as sophomorically as Trump did when explaining his solution to Middle Eastern terrorism: “I would bomb the s— out of them. . . . I’d blow up the pipes, I’d blow up the refineries, I’d blow up every single inch, there would be nothing left.”

As a candidate, Trump did not know what the nuclear triad is. Asked about it, he said: “We have to be extremely vigilant and extremely careful when it comes to nuclear. Nuclear changes the whole ballgame.” Invited to elaborate, he said: “I think — I think, for me, nuclear is just the power, the devastation is very important to me.” Someone Trump deemed fit to be a spokesman for him appeared on television to put a tasty dressing on her employer’s word salad: “What good does it do to have a good nuclear triad if you’re afraid to use it?” To which a retired Army colonel appearing on the same program replied with amazed asperity: “The point of the nuclear triad is to be afraid to use the damn thing.”

As president-elect, Trump did not know the pedigree and importance of the one-China policy. About such things he can be, if he is willing to be, tutored. It is, however, too late to rectify this defect: He lacks what T.S. Eliot called a sense “not only of the pastness of the past, but of its presence.” His fathomless lack of interest in America’s path to the present and his limitless gullibility leave him susceptible to being blown about by gusts of factoids that cling like lint to a disorderly mind.