Call him “Patient 1”: An individual in Washington, D.C., who presents with symptoms of mental decline, including a bizarre inability to remember where his own father was born. Bandy Lee, a psychiatrist on the faculty at the Yale School of Medicine, has some insights to share, which we will get to in a moment. On Tuesday, at a meeting with the secretary-general of NATO, President Trump launched into an impromptu riff on one of his favorite topics, the reluctance of America’s wealthy European allies to pay more toward their own defense. Then, in what might have been a clumsy effort...