Are the differences in political attitudes between red and blue states unique to the American political system, or are they a more general result of the interaction between where voters live and income?

In our book we try to put the U.S. in comparative perspective by analyzing recent presidential elections in Mexico, in which there was also a profound regional divide between high-and-low-income states and a huge controversy over the votes of rich and poor voters. We also took a look at income and voting in other countries in Latin America, Europe, and Asia.

In a nutshell we found that the Northeast and West of the United States is like Europe, and the South is like Mexico. In other words, the rich states in the Northeast and West, along with much of Europe seem to have moved toward what might be called a postindustrial politics in which voters of liberal and conservative parties tend to differ more on religion than on income. In contrast, the poorer states in the South and middle of the United States seem to look more like Mexico, with a more traditional pattern of votes of the rich and the poor.

So, is the U.S. exceptional in terms of voting patterns? Here's what we found:

• Mexico shows regional voting patterns similar to the United States but there are important geographical differences some of which are associated with Mexico City (which is richer than any state but with a voting patterns typical of lower-income states).

• In general, income predicts voting more strongly in the United States than in may other countries of the world.

• The United States is far from unique in the importance of religion in voting

Now, what do all of these findings mean anyway? First, each country has its own political history (and yes, the United States and Mexico are very different from each other, just as both are strikingly different from Canada and Argentina). But, just about everywhere there are huge regional divisions and important differences between states within regions, and these differences shape people's voting preferences.

It is not just geography per se, it is how it interacts with voters' relative position in society. In other words, a person's political, social, cultural, and economic environment is made of both the people and the institutions that structure their daily interactions. As a consequence, as we suggest in our book as well as Nolan's work; people's voting decision is going to be shaped by both their socioeconomic status (aka income) and the composition of the local setting.