When I travel to Asia, I’m fairly often met at the airport by someone holding a sign reading “Mr. Paul.” Why? In much of Asia, names are given family first, personal second — at home, the prime minister of Japan is referred to as Abe Shinzo. And the mistake is completely forgivable when it’s made by a taxi driver picking up a professor.

It’s not so forgivable, however, if the president of the United States makes the same mistake when welcoming the leader of one of our most important economic and security partners. But there it was: Donald Trump referring to Mr. Abe as, yes, Prime Minister Shinzo.

Mr. Abe did not, as far as we know, respond by calling his host President Donald.

Trivial? Well, it would be if it were an isolated instance. But it isn’t. What we’ve seen instead over the past three weeks is an awesome display of raw ignorance on every front. Worse, there’s no hint that either the White House or its allies in Congress see this as a problem. They appear to believe that expertise, or even basic familiarity with a subject, is for wimps; ignorance is strength.

We see this on legal matters: In a widely quoted analysis, the legal expert Benjamin Wittes described the infamous executive order on refugees as “malevolence tempered by incompetence,” and noted that the order reads “as if it was not reviewed by competent counsel at all” — which is a good way to lose in court.