Andrew Gelman, a statistics and political science professor at Columbia, presented his co-authored paper "Rich state, poor state, red state, blue state: What’s the matter with Connecticut?" (PDF) on Friday, and it's well worth a read. The key point is that the pattern of poorer Republicans "red states" and richer Democratic "blue states" is a misleading guide to the relationship between income and party preference. David Brooks and the other pop sociologists are not giving us the whole picture.
Here's the key part of the abstract:
We find that income matters more in “red America” than in “blue America.” In poor states, rich people are much more likely than poor people to vote for the Republican presidential candidate, but in rich states (such as Connecticut), income has a very low correlation with vote preference. In addition to finding this pattern and studying its changes over time, we use the concepts of typicality and availability from cognitive psychology to explain how these patterns can be commonly misunderstood. Our results can be viewed either as a debunking of the journalistic image of rich “latte” Democrats and poor “Nascar ” Republicans, or as support for the journalistic images of political and cultural differences between red and blue states— differences which are not explained by differences in individuals’ incomes.
For decades, the Democrats have been viewed as the party of the poor, with the Republi- cans representing the rich. Recent presidential elections, however, have shown a reverse pat- tern, with Democrats performing well in the richer “blue” states in the northeast and west coast, and Republicans dominating in the “red” states in the middle of the country. Through multilevel modeling of individual-level survey data and county- and state-level demographic and electoral data, we reconcile these patterns.
To see how dramatically the influence of income varies by state, see figure 12 on page 18, which contrasts Mississippi (the state where income has the strongest influence) with Connecticut (the state where it has the least). Pretty remarkable. As Gelman said, rich white people in the South are to the Republicans what African Americans are to the Democrats.