That’s the message in a recent book, The Spirit Level, which argues that economic inequality, not overall wealth, level of poverty or cultural differences, is the chief reason for societal breakdown. The authors present a wealth of data, much of it showing the U.S. near the top of the charts among OECD countries for social ailments such as drug use, obesity, violence, mental illness, teenage pregnancy and illiteracy. The author’s central thesis is that the size of the gap between the richest and poorest is the key factor accounting for this performance. Income inequality in the U.S. is third highest among OECD countries, trailing only Mexico and Turkey.

Correlation, of course, is not the same thing as causation. One Swedish economist pointed out that an increase in economic inequality in Sweden has occurred in tandem with better health and gender equality. Our guess would be that America’s performance on a host of social and health indicators is impacted by a confluence of factors – demographic and social as well as economic – and cannot be attributed to economic inequality alone.

Still, it seems common sense that nations and communities that have lower levels of income inequality would have less class status issues and levels of resentment, and potentially higher levels of social cohesion. Certainly they would have fewer gated communities. That would be a good thing.