Golly, I agree with George Will about something. He says the state of Trump’s mind is so parlous that it amounts to a disability. I think that’s right.

It is urgent for Americans to think and speak clearly about President Trump’s inability to do either. This seems to be not a mere disinclination but a disability. It is not merely the result of intellectual sloth but of an untrained mind bereft of information and married to stratospheric self-confidence.

I’ve been doing that all along. In that area my conscience is clear.

What is most alarming (and mortifying to the University of Pennsylvania, from which he graduated) is not that Trump has entered his eighth decade unscathed by even elementary knowledge about the nation’s history. As this column has said before, the problem isn’t that he does not know this or that, or that he does not know that he does not know this or that. Rather, the dangerous thing is that he does not know what it is to know something.

It’s all three, and more. Let’s not be precious about it. Yes the problem is that he doesn’t know X or Y, and that he doesn’t know he doesn’t know. And then it’s everything else too. Everything about the way he thinks and talks is the problem.

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.”

Quite. This is why I keep saying there should be a filter of some kind to keep hopeless intellectual incompetence out of the presidency.

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.

Americans have placed vast military power at the discretion of this mind, a presidential discretion that is largely immune to restraint by the Madisonian system of institutional checks and balances. So, it is up to the public to quarantine this presidency by insistently communicating to its elected representatives a steady, rational fear of this man whose combination of impulsivity and credulity render him uniquely unfit to take the nation into a military conflict.

Or into four years of its existence.