INDIAN SPRINGS, Nev. — The peace walkers arrived sweaty and gross, feet blistered and knees creaking, and Phil was waiting for them. Phil had his signs up, his American flags out, his star-spangled cap on. He extended a tight-fisted thumbs up toward the cars exiting Creech Air Force Base. A couple hundred yards away, every couple of minutes, a drone glided earthward with a baleful elegance. Predator. Reaper. Reaper. Predator. Thanks for keeping us safe,” Phil said toward the driver of a white Ford F-150. If the driver had looked to the right, he or she would’ve seen Phil in...