For years, people treated Trump’s verbal nonsense as entertainment—the endless riffs about low-flow toilets, shark attacks, wind turbines and the late, great Hannibal Lecter. We laughed. We picked it apart. The media turned it into colorful copy, like some bizarre national reality show hosted by a guy with the nuclear codes. But watching Trump seriously claim that you need to be a top-of-the-class MIT graduate to operate a lawnmower—and that he personally freed the American backyard from this imaginary problem—is different. It sure as hell isn’t some clever metaphor for overregulation. Trump is dumb as a box of rocks but his cognitive decline is on full display tonight—and it isn’t a damn bit funny.