Imagine waking up one morning to the news that because of a recent court decision, you may no longer be your child's legal parent. Forget all those times you've read Goodnight Moon, those long nights you spent in a steam-filled bathroom trying to keep your sick child breathing. In the eyes of the law, you may suddenly be just a kind stranger. No emergency room, insurance plan, schoolteacher, tax man, or judge will count you as essential to your child.

Shouldn't it be enough of a task in life to find meaningful work and love, those north and south poles of happiness? No: The human animal, like so many of its two- and four- and many-legged kin, also has an enduring need to establish social hierarchies. And that job--figuring out your rank and edging it upward--requires acute attention in American culture, which is constantly reshuffling the terms of success. Tocqueville was one of the first to warn that Americans are ever-anxious about the social precipice, the real possibility of plummeting from upper- or middle-class respectability.