One sunny winter afternoon in western Michigan, I took a ride with Leon Slater, a slight sixty-four-year-old man with a neatly trimmed white beard and intense eyes behind his spectacles. He wore a faded blue baseball cap, so formed to his head that it seemed he slept with it on. Brickyard Road, the street in front of Slater’s home, was a mess of soupy dirt and water-filled craters. The muffler of his mud-splattered maroon pickup was loose, and exhaust fumes choked the cab. He gripped the wheel with hands leathery not from age but from decades moving earth with…