“Well no, of course not — we’re so much better than all that,” Mr. Johnson, a former New Mexico governor, said sarcastically. “We’re so much better when in Afghanistan, we bomb the hospital and 60 people are killed in the hospital.”

The remarks by Mr. Johnson came in an interview with The New York Times after a string of damaging stumbles when he has fielded questions about foreign affairs. After failing to recognize the war-torn Syrian city of Aleppo during a television interview Sept. 8, Mr. Johnson had another difficult moment on Sept. 28, when he vainly tried to name a foreign leader whom he admired.

In the Times interview on Wednesday, Mr. Johnson conspicuously sought to avoid another misstep. Asked if he knew the name of North Korea’s leader, Mr. Johnson replied, “I do.”

“You want me to name” the person, he said, then paused, before adding dryly, “Really.” But he declined to supply the name.