One of the best political science books I've read recently is Coming Apart: The State of White America (1960 - 2010) by Charles Murray.
Don't let the subtitle mislead you. Murray focused on white people to avoid conflating race with class.
(He may also have been trying to avoid the controversy surrounding his most famous book, The Bell Curve, which seemed to suggest blacks have lower IQs than whites.)
Murray believes America is coming apart, but along class not racial seams.
It doesn't do his thesis justice, but, in brief, he believes America's new class system is the product of homogeny-- our tendency to associate with people like ourselves.
Homogeny wasn't much of problem back in the 1960s, he says, because most people had roughly the same level of education, Only 8 percent of the population had a college degree. And people with widely different incomes lived in relative proximity to each other. As a result, we all shared the same basic cultural values.
But over the last 50 years, two mutually reinforcing trends changed that equilibrium.
Over those decades, more of us went to college. And America changed from a manufacturing economy to an information economy. Manipulating data became more important than bending iron, putting a premium on brain power.
College degrees became tickets to the best paying jobs in the new knowledge industries or professions.
Today, about 28 percent of Americans have college degrees. Those highly educated people tend to marry each other and to make their homes in neighborhoods filled with people just like themselves.
An elite class of college-educated, affluent knowledge workers was born. And over the last 50 years, they have been busily replicating themselves. Murray calls them a new "upper class." And they are concentrated in a relatively small number of communities.
In fact, Murray identified 882 zip codes where most of the residents are in the 95th percentile of education and incomes. That is, only five percent of other Americans have more education and higher incomes.
What Murray finds troubling -- and does a pretty fair job of documenting -- is how isolated these people are from the lives of ordinary Americans, not only physically, but also culturally. They have no idea how the rest of the country lives.
And what's particularly dangerous is that they are also the people who run most of our country's cultural, political, educational, and media institutions.
As Murray says (I'm paraphrasing), if a truck driver can't empathize with a Yale professor, it's not a big deal. But when the Yale professor, or the producer of the nightly news, or an advisor to the president, can't empathize with truck drivers, we're in for trouble.