What's important to recognize is that in the U.S. today, tens of millions of kids start life on a uneven playing field. Imagine having to try to run a race if you started ten yards behind everyone else, hadn't eaten breakfast that morning, or maybe even dinner the night before, had slept in your third homeless shelter that month and didn't have shoes that fit right. Catching up would be really, really hard. With almost 32 million American kids living in low-income families, that means four out of ten runners are starting far back.

The human impulse behind the isolation of class is as basic as impulses get: People like to be around other people who understand them and to whom they can talk.