Yusif Jones, standing in front of a long row of porta-potties, slides his plastic Trump mask over his face. “I’m him!” he exclaims. He puffs up his chest in his homemade Trump shirt. It’s a short-sleeved American flag pullover, onto which he has ironed black felt letters across vertical red and white stripes: GOT TRUMP? Then he flashes the O.K. sign, a silver ring on his pinky. “I’m him, dude!”

For Trump supporters like Jones, the O.K. sign—thumb meeting index finger, three fingers splayed—is a kind of secret handshake. It began as a joke—a “hoax” meant to trick liberals into believing that the raised fingers actually represent the letters WP: white power. The joke worked so well that it became real. Now, in certain circles, O.K. does mean white power—unless you say it doesn’t. Jones, a big, vein-popping, occasionally church-going white man burdened with what he calls an “Islamic” name by his hippie mother, revels in this kind of coded message, a sense of possessing knowledge shared only by a select few. It’s Möbius strip politics, […]