Richard Nixon saw himself as a true patriot, and he considered it his patriotic duty to strive to overcome his darker impulses and moods to exude an upbeat, optimistic outlook—an outlook he considered quintessentially American. He often didn’t succeed, but it was this struggle that made Nixon so relatable to what he called America’s silent majority. Most of us who aren’t natural-born, back-slapping politicians have also been there, struggling against our own shades of negativity.

Whatever you think of …