while race-based segregation has been slowly declining, class-based segregation has been increasing. - Robert D. Putnam

Slavery was, in fact, a social system designed to destroy social capital among slaves and between slaves and freemen.

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.

Without succumbing to political nightmares, we might ponder whether the bleak, socially estranged future facing poor kids in America today could have unanticipated political consequences tomorrow. So quite apart from the danger that the opportunity gap poses to American prosperity, it also undermines our democracy and perhaps even our political stability.