It was 100 degrees as the sun was setting, and a toddler with red curls was running toward the Ferris wheel at the National Mall, installed as part of the Great American State Fair. The kid was trying to get my attention — he seemed to like being the center of things. I looked around to find an adult he belonged to and realized how vulnerable a precocious little one (with an overactive set of legs) can be. His young father found him — too flustered, it seemed, to be worried yet and perhaps still learning how much his life ...