inequality of opportunity slows growth by keeping disadvantaged potential workers from developing their full capacity. - Robert D. Putnam

This geographic polarization was made possible by the growth of suburbs and the expansion of the highway system, which allowed high-income families to move away from low-income neighbors in search of large lots, privacy, parks, and shopping malls. This class-based residential polarization has been accelerated by the growth of the income gap and (ironically) by changes in housing legislation that enabled more affluent minority families to move to the suburbs.

Although “the American Dream” is a surprisingly recent coinage (the term was first used in its modern sense in the 1930s), the cultural trope of Horatio Alger and the prospect of upward social mobility have very deep roots in our psyche.

As inequality has increased,” she writes, “debate about the extent of mobility in American society has heightened. As income gaps have widened, the opportunity that children have to do better than their parents is increasingly important. . . . Whether they do so at a faster or slower rate than they did in the past is not a settled question. But since the rungs of the ladder are further apart than they used to be, the effects of family background on one’s ultimate economic success are larger and may persist for a longer period of time.”2