In the America of haves and have-nots, fewer folks are “movin’ on up” like George Jefferson of the classic sitcom. In a new paper for the Institute for New Economic Thinking, Peter Temin, MIT economist and economic historian, breaks down how it happened and where we’re headed with a powerful model first used by West Indian economist W. Arthur Lewis, the only person of African descent to win a Nobel Prize in economics. Dual economies are common in less developed countries, but Temin argues that America has now diverged into a top thirty percent, where children receive excellent educations and grow up to work in sectors like finance, technology and electronics industries (FTE)— and then there’s the rest, the low-wage folks who live paycheck to paycheck and whose kids have little hope of joining the lucky ones at the top. Temin explains what drives the dual economy, what race has to do with it, how children are hurt, and why our political system can’t seem to fix anything. *This post originally appeared on the blog for the Institute for New Economic Thinking.