The image of President Donald Trump’s mind as an empty wasteland—a void touched only by sudden storms and mirages—has a strong hold on members of both the Democratic and Republican parties. For Democrats, scorn for Trump’s intellectual abilities is of a piece with their rage at almost every aspect of his Presidency—indeed, at the very fact of his Presidency. And it’s as good an explanation as any for his Administration’s often incomprehensible actions. Sometimes his tweets read as the work of a malcontent tween, with boasts that are recklessly large. Other times, they contain assertions of Presidential power that seem to suggest that the plain language of the Constitution is inscrutable to him, or just uninteresting. Then there was his tweet this past weekend, in response to Michael Wolff’s new book, “Fire and Fury,” about his status as “a very stable genius,” which was almost self-nullifying: would a stable genius, or even a slightly wobbly, reasonably intelligent person, reveal his insecurities in such a manner?