In a new book, The Vanishing Middle Class: Prejudice and Power in a Dual Economy, Peter Temin, Professor Emeritus of Economics at MIT, draws a portrait of the new reality in a way that is frighteningly, indelibly clear: America is not one country anymore. It is becoming two, each with vastly different resources, expectations, and fates.

...

The two sectors, notes Temin, have entirely distinct financial systems, residential situations, and educational opportunities. Quite different things happen when they get sick, or when they interact with the law. They move independently of each other. Only one path exists by which the citizens of the low-wage country can enter the affluent one, and that path is fraught with obstacles. Most have no way out.

The richest large economy in the world, says Temin, is coming to have an economic and political structure more like a developing nation. We have entered a phase of regression, and one of the easiest ways to see it is in our infrastructure: our roads and bridges look more like those in Thailand or Venezuela than the Netherlands or Japan. But it goes far deeper than that, which is why Temin uses a famous economic model created to understand developing nations to describe how far inequality has progressed in the United States. The model is the work of West Indian economist W. Arthur Lewis, the only person of African descent to win a Nobel Prize in economics. For the first time, this model is applied with systematic precision to the U.S.