I led off this week's discussion with a quick review of our main findings along with a plea to discuss some open questions about the sources of some of the changes in American politics in the past few decades.

In response, Nolan McCarty referred to evidence that the Democratic and Republican parties in Congress have moved apart on the issues, and, at the same time, the economic gap between rich and poor has increased. As a result, rich and poor people remain distinct in their voting patterns--even amid the cross-cutting social issues that have led casual observers such as Michael Barone to mistakenly suppose that the Democrats are now the party of the "trustfunders" and the Republicans are the party of the "common people."

That said, we shouldn't overstate the extent to which voting is determined by one's economic status: in 2008, Obama received about 50% of the vote of people with family incomes over $150,000. Nolan also discussed the role of religion in voting. As we discuss in chapter 6 of Red State, Blue State, religious attendance is basically uncorrelated with income: rich and poor are equally likely to be frequent church attenders. Nolan goes beyond our discussion of public opinion to consider some of the structural reasons why religious people are voting Republican at a rate that wasn't happening before 1992. For example, as late as the 1980s, there was no difference between the average attitudes of Democrats, Republicans, and Independents on abortion:

To continue on the dimension of social issues, Eric Rauchway pointed out the importance of racial voting, and Steve Sailer elaborated on his story of geographic separation being caused by rising home prices in economically booming coastal cities. Each of these ideas, along with the partisan polarization story, tends to be presented on its own, and in our book we tried to put these together. I wouldn't say we came up with a grand unified theory--we juxtaposed all these ideas more than fully integrating them--but I hope we facilitated future understanding, if only by presenting graphs that would rule out various simple hypotheses.

Finally, Matthew Yglesias, Aaron Swartz, and Eric Rauchway steered the discussion to the topic of how the ideas in our book might be relevant to political activists. No, I don't think that John McCain would've won the election with a different pitch--just as I don't think Michael Dukakis could've pulled it off in 1988 had he only had a better message. 2008 was a Democratic year. But I was able to draw some advice from our book, which I provided free of charge to the blog readers, on the hope that it would be good for activists of both parties to be more aware of what the voters are interested in. And, as Swartz, Rauchway, and Sailer discuss, there's a lot more out there that political activists can do.

Pretty much all my analysis is of public data. For example, the Pew research website is right here, and I don't think it will take much searching for you to find the National Election Study, the General Social Survey, and all the rest. So I encourage you to read our book carefully (as well as my ongoing research, some of which appears here and here)--and if you want to disagree, go to the data and draw your own graphs, and your own conclusions. The book was intended to be empowering as much as it is authoritative.

Finally, I was sorry to see that Nathan Newman and Will Wilkinson did not present their contributions to the discussion. Maybe something is still forthcoming?